Here I'm rating the class entry feats and any significant feats that require the class entry feats. Feats that require the class are currently in the various tier ratings, but I'll move them here eventually. The rating for the class is my general rating for how good it is, all in all, to take the class. It includes other feats that the class opens up, paragon paths the class opens up, and the quality of the entry feats.
Practiced Killer (D400)
+1/2/3d8 1/enc. Yay. Good choice of skills though, access to all the assassin feats, and by intent probably access to the "any martial" feats too.
Shadow Initiate (D382)
+2d6 1/encounter. Yay. Stealth is good though, and assassins have some interesting powers... but no killer feat support yet. Basically strictly inferior to Practiced Killer in most aspects.
Deific Instrument (D386)
Assassins can already use your sword as an implement, so the benefit is negligible.
Oathbound Stalker (D386)
Two more squares to all your teleports doesn't suck, but feats are 'spensive these days.
Vengeful Shade (D386)
A second feat to have the 1/encounter shroud damage be radiant. Er, yay. Pass.
Student of Artifice (EPG)
The base Artificer MC feat, Healing 1/day plus a skill you don't have but would be good at.
Great powers, if you have the strength.
Berserker's Fury (PHB2)
+2 to static damage for an encounter. Boo Ya.
Rampant Fury (PP)
Only works with Barbarian powers, and only Eternal Seekers can have enough of those to matter.
Bravo (D373)
Intimidate isn't a bad choice, and +2/+2 for two turns is a great choice. But the lack of higher level support means it loses value. Train out by paragon.
The main draw here is grabbing Battle Cleric's Lore via wording abuse and taking Divine Healer . A 2nd benefit is that Radiant Advantage is probably the best Perma-CA feat you could take, if you make it to epic. A 3rd benefit is taking Domain Synergy for +2 to hit with Chargespam.
Domain Synergy (D379)
I didn't even bother to rate the channel divinity feats for the domains, because a feat to use a lesser-powered encounter power instead of your already aweseome power? Lame. But a second feat to basically get a free +2 to hit with Overwhelming Strike ? Not lame. And two feats for +2 averages out to +1 per feat, which is a fair price. (The channel divinity granted by Divine Excellence is super easy to trigger. Trivially, if you're a wood elf)
Divine Healer (DP)
The point here is to take advantage of Battle Cleric's Lore feature substitution, to get an pseudo-shield that doesn't require dropping the Manga weapons. Nearly mandatory for Str/Wis avengers, due to the Scale proficiency. Of course, RAI was likely not to give the substitution feature in a multi-class feat. So your DM may vary.
Gambler's Word (D379,Paragon)
The Cleric MC feat gives you one healing word per day. This should move it up to more than one per encounter.
Initiate of the Faith (PHB)
You already have religion and Holy Symbols, so it's just Healing Word 1/day.
Radiant Advantage (DP,Epic)
Get your CA on anyone you hit ( Painful Oath ). Works best as part of the Radiant package, but everyone likes +2 to hit... retrain out Deadly Draw to make room.
Fighter gets the blue for Kensai and Slashing Storm. Plus the investment in Strength opens up Power Attack.
Battle Awareness (MP)
Off action attack, although one you can't really force to happen when you want.
Slashing Storm (MP2,Epic)
+Wis_Mod to DPR, basically, again. Not quite as good as Painful Oath, because it requires an MC feat... but affects all enemies adjacent to you, so better for keeping your oath. And has some light control that might cause enemies to walk away from you.
Student of the Sword (PHB)
Training in a skill from a rather poor list, and a once/encounter mark. The mark comes with a +1 to hit, but that has to be declared before the attack, which means it's not really big enough to matter much.
Divine Secretkeeper (DP)
Training in a decent skill for Int-based, and Ritual Casting.
Acolyte of Divine Secrets (PHB2)
You already have religion, and using an at-will once per encounter doesn't seem that good unless it synergizes particularly well with what you do.
Blue for Githzerai, due to Zuoken's Centering . A couple of PPs are at least decent, but non-gith aren't getting too much out of the feat space since most Monk feats focus on the flurry mechanic. Your entry feat ( Monastic Disciple ) will get you a skill, and a 1/enc "2+Wis_Mod damage and slide" damage feature that never scales. (Well, at paragon, you can also use it to move someone out of the way for the 2nd attack in the sequence, but that still means you got your 1st hit without Oath. Friends don't let Friend Avengers attack without Oath). Or alternately it will get you a skill and an encounter movement technique ( Monastic Adept )
Zuoken's Centering (D378,Githzerai)
Rebase surges and Athletics on Wis. In most campaigns, I'd guess rebasing athletics is more important, but if your DM wants to run you low on surges, this is how you stop that.
Centered Intuition (PP,paragon)
Danger Sense called, and wants to know why you're adding two Preqs for a 1/20 chance of a +5 bonus to initiative. In reality, not relevant. Monastic Disciple doesn't give you the class feature, just the ability to use it.
Channel Might (DP)
I'm not sure why you became a Paladin, but since you did pick this up. +1 to hit with your RRoTd power
Champion's Countenance (D388,Epic)
For Masters of Defence only. Spread the love. None of the rest of you will spend enough time at maximum hit points to notice.
Divine Channeler (DP)
Does the Ardent Paladin's CD Divine Strength seem interesting? Cause I think that's the best choice here.
Mercy's Reward (D388)
Turn a crit into healing. While you could generate a lot of healing, surges are limited and most of the time killing monsters will be the better path. So don't think "how much healing I can get", think "how likely am I to crit on the one round where a normal hit would still kill the monster and we need healing and the leader is out of healing." If that's likely enough to take this feat, then your party has problems. Of course, users of Dice might think it's reliable enough anyway.
Soldier of Faith (PHB)
Training in a skill from a decent list, and a once-per-encounter mark that does zero damage.
Soldier of Virtue (DP)
Virtue's Touch? That's a leader thing...
Virtuous Recovery (DP,Paladin)
Martyrs: resistance equal to Wisdom modifier multiple times a combat.
Slashing Storm (MP2,Epic)
+Wis_Mod to DPR, basically, again. Not quite as good as Painful Oath, because it requires an MC feat... but affects all enemies adjacent to you, so better for keeping your oath. And has some light control that might cause enemies to walk away from you.
Two-Blade Warrior (MP)
Twin Wielded Waraxes for the Twin-striking Win, and the Ranger has a nice list of skills to choose from.
Warrior of the Wild (PHB)
The ranger has some nice skills to choose from, but did you see Two-Blade Warrior? Dual Wielding Waraxes beats the stuffing out of a d6 to damage for two rounds.
Prime Hunter (MP,Epic)
If Cunning Stalker is your CA feat, here's another +1 to hit to make sure that Power Attack makes sense. I'm having a hard time rating this above black, even though it gives bonuses to hit, because your ED likely gave you a bonus to hit, and our leader should be giving out silly bonuses to hit. And the feat still isn't free. Also, like Cunning Stalker , it makes focus fire harder in parties with multiple melee.
There certainly should be synergy from a stat-sharing, role sharing class. But the intro feats don't work out as well as you'd think, nor do the PPs (anymore).
Ruthless Efficiency (MP)
Being able to use Maces for Rogue Powers is pretty useless, but training in the stealth skill beats training in Thievery.
Sneak of Shadows (PHB)
IMHO, Thievery is kinda useless, but sneak attack isn't. But it's still just a few d6, and you've got to work to have the right weapon handy.
Sly Dodge (MP)
Bluff? Where exactly did this Charisma score come from?
Spiked Chain Training (DA2009)
Giving your weapon the Light Blade type means you can take Nimble Blade , for an extra +1 to hit, and Deft Blade for an effective +3 or so on MBAs, but it costs yet more feats and your Multi-class slot. Spiked Chains don't quite have enough support to take, but this one feat offers some nice value.
Heart of the Blade (AP)
Gives different skills, but the granted class feature is rather useless fluff.
Blade Iniate (FRPG)
A skill you don't have, but would be good at, and a solid bonus to AC for one encounter per day.
There was a nice Student of Caiphon synergy. But SoC got gutted by errata, and now Warlock offers very little.
Student of Malediction (AP)
The ability to leave the target cursed (by choosing not to do the extra damage) opens up more Warlock options. But not many.
Pact Initiate (PHB)
The Cha 13 requirement is annoying, but not impossible. The skill list isn't great. Counting as a member of the pact for Paragon Paths is kinda required for Student of Caiphon.
Starfire Womb (D366,Warlock)
Free save every time you hit with a lightsaber (or any other radiant attack)
Arcane Initiate (PHB)
Prefer another entry feat, as Wizard at-will powers are useless for you, except for Thunderwave.
Learned Spellcaster (AP)
Ritual Casting is more useful to you than a wizards at-will power once/encounter.