Feet

Properties

Acrobat Boots(PHB,2)

Bordering DeepSkyBlue for martyrs.

Assault Boots(AV,12)

Knock prone on a crit. Better with other crit effects added in (like the monters is now Dazed and in a zone of damaging Radiance. Just hypothetically). But at the worse that's +2 to hit for a half-turn.

Boots of Adept Charging(AV,2)

Required equipment for most Chasers. If you can end the turn not adjacent to your Oath target, the odds go up that it will wander elsewhere. Also, if you want to charge repeatedly, you need two squares between you and your target. Overwhelming Strike will give you one square, this gives you the second.

Boots of Caiphon(AV2,24)

At-will large shifting (as a minor) is a great help to getting your oath, and the bonus to Ref is also nice. At this level, the damage you take is negligible. But you could find some boots of teleportation, or Zephyr boots. Better if you've been trained by Davros

Boots of Striding (and Springing)(PHB,9/14)

Speed is always good, bonuses to Athletics checks are better. But Greaves of Maldeen have more speed.

Boots of Speed(PHB,22)

Booring old +2 to speed. And a daily power to replace your Boots of Eagerness. For nova builds, I'd rather have the encounter power, but +2 to speed is hard to argue against.

Boots of the Fencing Master(AV,7)

Basically, +1 to AC and Reflex each turn you wouldn't otherwise move. Since you sometimes have rather tight positioning requirements, I think it's overrated. However, you can pick it up as Davros Elden's Defensive Step , which prevents it from taking a slot. That's nicer. And once you hit Epic, there's a feat to add one to any shift you do, which means the cost for the AC just went down.

Boots of Teleportation(AV,28)

Never take unwanted OAs again. Teleport to the couch to pick up the remote... At high level, it's either these or Zephyr Boots. Accept no other substitutions.

Eladrin Boots(PHB,16)

While you may have a large number of teleportation powers, most of them are "adjacent to the enemy", so these don't help as much as you'd think.

Greaves of Maldeen (D364,12)

+2 to speed, basically. Yeah, there's a constraint, but it will never come up. And a power to help keep closer to someone.

Sandals of Avandra(AV,25)

The same +2 speed as Boots of Speed, but with a nice at-will mobility power and a nice encounter power. Greaves of Maldeen are much much cheaper though.

Sandals of the Temporal Step(PHB3,16)

Listed here and in the Utility section, with different ratings. Here, it's a rather expensive +1 speed, with a nice utility power. There it's a spectacular utility power in the right hands, with a nice property.

Spark Slippers(AV2,16)

Looks nice, you but won't have a charisma modifier.

Zephyr Boots(AV,24)

Fliers are a huge problem for Avengers, and this is how you solve it.

Utility

Boots of Eagerness(AV,9)

Free move every encounter, but uses your minor. You've probably got better utility powers that serve the same need.

Elven Boots(PHB,11)

More speed is always good, but I'd rather have +1 speed always than +2 for a turn that costs a minor action to invoke.

Feystep Lacings(AC,12)

Get out of grabs free, 5/day. Or adjust your position 2/day. Roughly.

Flanker's Boots(AV,15)

A great way to find the right square to attack from. But over priced. If you want these, pick up Feystep Lacings instead, for half the cost.

Sandals of the Temporal Step(PHB3,16)

Some extra speed as a property, and an extra minor action once per day for your nova turn.

Winged Boots(PHB,13)

Fliers are a huge problem for Avengers, but one round a day is not the solution. See Zephyr Boots when you can afford them, and Grasping Javelins until then.