I was bored waiting for the L4D2 demo so I downloaded the Torchlight one and I have to say its combat is one of the best I've seen in an ARPG. It's simple and arcadey, but somehow extremely satisfying.

Think of a polished Diablo I with the exact same structure and made by some of the designers of Diablo and Diablo II.

It's a shame it has only three classes and no multiplayer at all, but it's still a nice single player game and it even has a netbook mode that lowers the graphics to make it playable on shitty computers.

http://www.torchlightgame.com/
http://store.steampowered.com/app/41510/ <- Demo



Apparently there's a F2P MMO coming in about two years, which could be really interesting if they really manage to maintain the same combat.