Wait...those are not crappy video cards? To me, those are ultra high-end. I always set my bar at $100...right now, a Radeon 1600 XT is the best value for the money you can get, but the coming 1650 XT will be pretty darn nice too. With $100 for that card, that system can play just about any game out there...by dropping $75 for a card, or maybe even a bit less, you can still play a fair bit of stuff, just nothing released in teh last year.

But, game-wise, I've got a couple reccomendations:

Third Person Shooter:
Armed and Dangerous--if you like to watch stuff blow up, this is your game. If you like to see 50 enemies crushed by giant boulders, this is your game. If you like seeing enemies catapult through the air after being hit by a rocket, this is your game. And this is the funniest game I have ever played...some cutscenes are solid gold. The only problems I found are that it can get repetitive and is very simple, but it just points to a certain type of gamer.

Freedom Fighters--Much more tactical and slower-paced. This is a squad-based shooter with a huge emphasis on the squad aspect of it...actually, to be honest, I found the shooting mechanics frustrating and lackluster. But the tactics of the game are spot-on, and it is a more methodical game for a different audience.


FPS:

Serious Sam: The Second Encounter: Pure chaos...enemies come from everywhere, just asking to be blown up. Requires ZERO thought, just reflexes, a trigger finger, and the will to stop from freaking out when 10 walking mech-fish, 3 guys with chainsaws, 15 animated bone dogs, 4 demons, 8 bull-things, 5 flying harpies, and 10 headless guys with bombs in their hands are all bearing down on you. The co-op is legendary, and the game can be as intense as any other out there. And, since the game is a 2000 or 01 release, it can run on a really basic system.

Painkiller: Like Serious Sam with amazing weapons, amazing enemies, and a gothic theme to it. I just played 2 of the 3 demos this weekend, and in pure fun, this was one of the best FPS experiences I have had in a good long while. A game that is just plain COOL. If you've never seen Havoc physics in action, this game will show you to the light.

Halo, Call of Duty, Return to Castle Wolfenstein: Enemy Territory: You can't beat the classics, and these all run on pretty basic PC's.

Soldier of Fortune 2: Tactical Action at its finest in this fairly old FPS. Very difficult and unforgiving, but relaly makes you feel like a lone commando trying to kill off a whole base...it is definitely not for the twitch crowd, though.


And, while I'm at it, I've got to reccomend Trackmania. It's a racing game, which you're not asking for, but it's simple, it's a lot of fun, it's like nothing else out there, and it can run on a laptop. Not like a Dell XPS laptop, but like my dad's business laptop downstairs. And it's a heckuva lot of fun.


So, overall, out of those, my faves are definitely Painkiller, Call of Duty, and Armed and Dangerous, but they are all options. Closest to MP2 would probably be Soldier of Fortune...it's actually kinda close to being a first-person MP2, without the slo-mo aspect. It's hard to find good PC third-person shooters these days, though.

As for the HL2 question, I would say probably yes. Half Life 2 runs on the amazingly scalable Source Engine, which can dial the Directx setting all the way down to Directx 7. If you've got a video card made in the last 5 or 6 years, you can run HL2 easy...you might be able to go back even farther than that.

__________________
My gh3d.com checklist:

[X]: Get something stupid I said in somebody's sig--Thanks Magus
[X]: Get a custom title--Very clever
[-]: Win more cool crap (Now impossible)
[X]: Suck up to Der Affe to get all this (Seemed to work...)