You should, I run an AMD Athlon 64 X2 4200+ and I can run it on full graphics just fine. I also reccomend the S.T.A.L.K.E.R. games, best FPS games I've played to date. The only problem is that it sometimes does feel like you're all alone with no one helping you. =/
Also, not sure if this is what you're looking for, but there's a space game called Freelancer that's open-world and sort of hack'n'slash. You control pretty much every aspect of your ship (shooting, speed, maneuvering, etc.) and you usually have other people with you.

