It all depends on the particular game.
In my last campaign we used quite a lot of powerful stuff (incantatrix+metamagic reducers, reach spell+persistent spell cheese, wish loops for cool stuff only (our castle), DMM persist CoDzilla, etc). In the campaign we're starting in 1 week or too however, we're aiming much lower (around tier 3 power level, no tier 1-2 classes, no uberchargers, no persistent spells etc.)