You can indeed go on Google, or Wikipedia, or just go on YouTube and check out game-play videos of the titles you're interested in or curious to know more about. I posted the list so that you could just pick up the ones you might want to look more into by yourself, that's about it, take it like a list of ingredients to get at the grocery... I don't know man.
Alright so erm... ok, out of them I would recommend that you play Borderlands (with or without DLCs, but with them is better, in my opinion), the original BioShock, original Half-Life along with Blue Shift, the very underrated Dark Messiah, the nearly-forgotten Prey, I'd also go with Quake 4, Crysis, Crysis Warhead and the original AvP. There, a more precise list of recommendations. As a side note I own 90% of the games on the list, and I played (not finished) them all.
EDIT: Oh yeah, and Borderlands is on sale right now on Steam, forgot about that.