Bleach filler is hit or miss. I liked the arcs with the little princess and the first half of the Zampakto rebellion was pretty good. Naruto filler isn't bad in small doses. Too bad we only ever seem to get it in HUGE chucks. One Piece filler is, with a few exceptions, horrible.
Stupid Kenshin filler arc.. Worst thing about it was that the series was canned before we got the other part of the content it was filling in for. The flashback was handled well in the OVA, but everything back in the present with Enishi was never to be seen short of maybe two shots in the final OVA. Criminal.