The Eberron Player's Guide deliberately does NOT require characters with a given dragon mark are of the "correct" race. But your DM might, especially if you are trying to join a dragonmarked house to train in the paragon path. So I've noted the "expected" race.
Deneith Protector (EPG,Human)
Get your Defender on. For the Martyr Master of Defense, but not your strongest choice.
Kudarak Ghorad'din (EPG,Dwarf)
Good powers for a chaser, even if it's not more damage. You'll want to have acquired Thievery though (backgrounds?) The daily power though is weak, as it's not melee, and it doesn't use an implement... but it does dispel zones even on miss.
Medani Trueseer (EPG,Half-Elf)
Ignore the picture of the guy with the double sword: all the attacks are ranged, and so don't get your oath bonus. It is good flavor, but the crunch is lacking.
Orien Swiftblade (EPG,Human)
Good mobility. You can use Int as your attack stat, which Martyrs like. But nothing to focus damage.
Phiarlan Phantasmist (EPG,Elf)
Ninjas like the Invisibility, but the attacks are Int or Cha based, neither of which a Ninja has. You wanted the Other house of Shadow paragon path.
Sivis Truenamer (EPG,Gnome)
Has the same "refresh Divine Rage" as Unveiled Visage, but with clearer language so that even I think it works. Your healing surge value shoots way up and you spread healing around, so it can help a Leader Minor. In the end, the path's focus on ranged powers dooms it to purple.
Thuranni Shadow Killer(EPG,Elf)
Invisibility ninjas like, stealth to your whole party, and a sweet striker damage feature for a nice good base. Then the e11 hits it out of the park, with a true multi-attack that also applies viscous effects. And then the u12 and d20 aren't bad either.
Champion of the Vigil (D390,Circle of Smoke and Whispers)
One for the Ninjas. Crit range of 19-20 while hidden is the main draw ... but the extra reroll doesn't hurt any. Make sure you can frequently become hidden. The encounter power doesn't get rerolls, but has an important effect an is an immediate. The utility power solves hiding problems for an encounter, and the daily is a nice alpha-strike power (free action to grant all your allies a free attack? Yeah, that's a daily)
Contract Killer (BoVD,Evil,Stealth)
A bunch of small bonuses that don't add up to anything