Man, when you really start to think about this generation of console games, it's much easier to list the final boss fights that didn't suck.
Gotta go with Fable 2 as the worst, though. Borderlands, Demon's Souls, Bioshock, Batman: AA - all had horribly easy final boss fights, but they were at least fights.
As for good final bosses, I'd say Darksiders, God of War 3, and Infamous did pretty well for themselves. I had to try more than once to beat these games, which is really saying something with today's difficulty curves.