I'm surprised we haven't seen Jake (GreyAlien) posting in this thread yet ;-)
Me too. Jake actually uses an advanced system in his framework that is mostly fixed rate logic, but does also include some tweening and jitter correction (for when those pesky background processes get in the way). I personally don't feel a need for all the tweening, but Jake is something of a perfectionist (only kidding ;o) ).
I don't actually own Jake's framework, but I'm sure he's designed his framework to be as flexible as possible for every game type. My games, so far, have had no real need for anything more than simple fixed rate logic. I always adjust the timing scheme depending on what's best for the project in mind.