of course, my most favorite is when ichigo rescues rukia, and in a split second defeats 3-4 leuitenants.... ownage.

my 2nd favorite is 44-45 when ishada is fighting the technology captain whose name escapes me right now... so awesome.

ok, third fave:
people will flame because it is a filler, but one of my favorite episodes was episode 91 (yes... during the bounto fillers) when ichigo pulls zangetsu into him and then goes bankai..i was so excited when i first saw this ep and i must have watched that episode at least a dozen times.