Bayonetta, hands down.

Easily Bayonetta and its sequel.

I also enjoyed Onimusha 2, God of War 3 and Devil May Cry 1 & 4 a lot.

Easily the first Devil May Cry, but I think Bayo 2 might be able to surpass it!

Diablo II for me, hands down, followed by Titan Quest and Sacred.

roblox

Bayonetta 2, followed by Bayonetta 1 and Hyrule Warriors.

I don't have much experience in the genre, really. Trying some of GoW 3 and one of the PSP ones a few years back did not inspire me to want to play any more of them, but I'm more receptive to the genre in general now so maybe I'd react differently?
Outside of that I've played Metal Gear Rising Revengeance, a couple hours of some Dynasty Warriors game, and now Bayonetta.

All I know from that is Bayonetta's can be pretty fun and is the best time I've had with a hack & slash so far! The QTE prompts are a little eh, though. Looking forward to moving on to the sequel. (: Might be awhile, because this is hard to get good at.

God of War with Devil May Cry a close second, but Devil May Cry is sadly not always good

God of War 1, 2 & 3 by an absolute mile.

Onimusha series is my favorite followed closely by the God of War series. I also like the Ninja Gaiden games. Recently beat the first Bayonetta its pretty good but has a few to many cut scenes for my liking. Also currently playing Darksiders 2 which is very good.