The Halo Series - I have over 1 month of gameplay on Reach which was my first game, I started playing 3 with a few friends and got a few days up on that in custom games and then I've got about 6 or 7 days on Halo 4 (Haven't enjoyed it to much tbh)
The Naruto Ultimate Ninja Storm Series was great not very popular though.
The Pro Wrestling games (WWE & TNA), I put a lot of time into these.
The Prince of Persia series (Excluding the "Prince of Persia" game. That was fucking shit.) This was my child hood, when I was about 7 or 8 my dad got Sands of Time on the PS2, spent hours playing that every time I went to his, then we got Warrior Within and Two Thrones and I played through both of them 3 or 4 times. I also bought The Forgotten Sands when that came out and I've played through that twice. I just love the Prince Of Persia series.
I haven't really played to many other games heaps, that's about it.