[4e] purchasing advice, and why warlords?

[Dimers]

On hitting Non-AC-Defenses (NADs):
Fortitude - AC averages to -1.39
Reflex - AC averages to -2.75
Will - AC averages to -3.31
So with a +3 Proficiency weapon, you have about the same chance to hit as an implement wielder attack reflex or will. If you have a +2 weapon, you are a bit better off then an implement wielder attacking Fortitude.

Heh. Hitting NADs. I take it, then, that there's no "Implement Expertise" to match?

To further explore the warlord topic, I'll also ask: which powers in the first PHB stand out the most in terms of aiding allies, and why are those better than level-equivalent powers of other classes? Artanis's example of Commander's Strike is a good starting point. When I looked at that, I just thought "oh, that's a plain attack plus a little extra damage". Now that I've spent a moment thinking about it, it's also much more targetable than melee at-will powers are, since it can affect any monster in melee with an ally anywhere, and it could potentially be boosted by bracers of mighty striking and gauntlets of ogre powerdestruction. Much better than the first glance indicated. So what else is strong?