Final Fantasy - Definitely. If I remember (Which I probably don't), there are about 13 ones and then a few other spin-offs... Needs to end.
Halo - Compared to some of the other games in the poll, 3 in a series isn't very much. I also haven't played it, but from what I hear it's similar to most FPS' (Run, shoot, cutscene, shoot, teabag, shoot).
Crash Bandicoot/Spyro the Dragon - Are they still making Crash and Spyro games?
Guitar Hero - Yeah, this could probably be stopped soon. Stick with World Tour and just update it with new songs.
Grand Theft Auto - Yep.
Gears of War - Same with Halo. 2 games in a series isn't very much. There's probably going to be a third one to tie up a few loose ends from GoW2, but after that I don't think there should be any more.
Legend of Zelda - Are these still being made? The last one I saw in a store was Phantom Hourglass, and I haven't heard any news of others... Eh, still needs to end if it hasn't already.
Mario - Stop beating the dead horse, dig it a grave instead.