well, from what I've seen, there're many people out there that like computer games so, what one do you like? my favorite right now is portal. so much so that I'm making a map pack
The Original Command and Conquer. yeah thats right. Old School right there XD. the Half Life Series and Portal was amazing too. Doom. Wolfenstein 3D. all the classics. Too many to list XD
Without a doubt in my mind, it has to be Fallout 1&2 Myst and the LucasArts games come in close but they just don't compare to the awesomeness of Fallout (!)
No competition... I'm a Ryzomer. But in the realm of non-MOs, C&C, definitely. Never played the original - first I played was RA2, and it's still my favourite.
I'm more of a console gamer than a computer gamer, but I will say without hesitation that my favorite computer game (and thank you for saying "computer game" rather than "PC game" and not excluding Mac users) is Minecraft. I've heard it said that it's like Lego for adults, and that's something I can agree with.