I don't have it installed atm but I do have it and used to play quite a bit of CS:S along with MW2. I have orange box but absolutely hated TF2. Although to be honest hated TF when it came out as a quake1 mod, dunno why I thought I'd like it 14 years later.
I cant play FPS games on consoles. Thumb-sticks suck.
I started serious gaming on the computer and, like you, couldn't play console fps shooters for the longest time. Once I hit college console games became far more convenient. I had a great desktop computer at home that did really well with video games, but even though I got a "gaming" laptop it couldn't quite handle the better video games out there so I lost touch with steam.
Now that I have a better desktop again I play a lot of good games with ease.
A few games I'd recommend that are relatively cheap:
Day of Defeat: Source
Torchlight (if you're into top-down fighting games like Diablo)
Left 4 Dead and Left 4 Dead 2
Natural Selection 2 - This is one of the more interesting fps's out there because it also involves some real time strategy. It pits a group of marines versus a group of aliens and each team has a commander responsible for several duties. You have to capture resources areas as foot soldiers/aliens and build resource extractors. The more resources you have the more things you can do (i.e. Marines can research better weapons, teleport technologies, etc.). Eventually who ever takes down the enemy commanding chair wins.
Unfortunately this game is in beta testing right now so it isn't available just yet unless you're ready to pay full price for the game.. I've had it since Alpha testing and it's come a long way, though.