CharlesGrey: Titan Quest is/was awesome. One of the best "Loot-'em-Ups", and one of my all time favorite PC games. :)
Darkstone is OK if you like the genre, but it's not particularly unique or special in any way. Does kinda have that Diablo 1 feel, though.
opticq: Oh my god that looks amazing. I loved Diablo 3, any more recommendations? I think I will definitely get TQ
I always found it funny how Diablo 3 doesn't look significantly better than Titan Quest & Immortal Throne, despite the age gap between the games. Anyhow, TQ has a lot of cool stuff going for it, such as the interesting skill tree system, the varied settings, and the mythology theme, if you're into that. Oh yeah, and ragdoll physics for opponents, which can often lead to all sorts of hilarious moments. :D
Also check out Grim Dawn, which is the project the former TQ developers are working on ( or some of the TQ developers, anyway ). I think it's still in development, but should be getting close to release by now. I hope it will find its way here when it's done.