So I just recently installed Windows 7 on my Macbook and I'm looking for games to play.  Now, when it comes to PC games, I tend to play games like Diablo, Titan Quest, World of Warcraft, Dungeon Siege and Torchlight.  So I'm just looking to see if anyone can help me find other games that are similar that I should "acquire".

Might I point you towards the thread currently raging against pirates? 

Unfortunately I haven't been able to play the game yet (due to my "weak" PC), I only recommended the game because it's similar to the examples you gave in your original post, also I'd recommend Dragon Age: Origins.

" @GIVEMEREPLAY: That thread seems pretty irrelevant to my existence as the argument for it or against is pointless right now and has nothing to do with my question. "

Return to the lowest depths of hell that you crawled out of, Pirate!

I loved The Witcher, it's a great game. And yes, the combat is a bit slower than other games but not in a way that's limiting. One of the best RPGs you'll come across. I really can't think of what it's similar too.. It's pretty much click-oriented, kind of like Diablo, but instead of insane clickage, it requires timing as well. There's a bit of strategy involved, though mainly for what fighting style you use.  Go look on YouTube for some gamplay since there's none on the site. 

I'd also recommend Batman: Arkham Asylum. I found that it was a fantastic PC port and even if you're not the biggest batman fan, the gameplay and story are still riveting.
 
And if you get it, buy it.

" The Witcher ;) "