Akki used the full respec to take the flavor of the month darkness powers instead of Ebon Rift, which didn't work as advertised. She's, like, 15.
Zenith was the new level 1 power armor character I made. At level 6 I respecced out of the tier zero attack into eye beams, which looked like it had stupidly good damage per endurance and could stack with other powers. This was a horrible, horrible mistake. The main problem with stacking power armor attacks is the 15% surcharge on power costs, which laser eyes inflicts in full in return for doing basically nothing. Eventually I took micromunitions and killed everything with that (which was hard, it's an aoe power and not really any good for single target use) until they awarded a full respec after the latest round of nerfs, then respecced into the flavor of the month power armor powers (minigun, in particular) which work much better.
Then Halo 3:ODST came out, so last night I played that instead. It's pretty hard, so far. It doesn't really play much differently than the normal halo games (you don't have a shield, but you have 'stamina' which works pretty much the same way -- a regenerating buffer before you start losing actual health) but the levels are a little trickier. If you don't sneak around you'll walk right into ambushes and die a lot. Not that I've gotten very far or anything.