GLSL?

[DoomerMrT]

I've bought my card (8800GTX) for 700$ in February, and it runs very fine in all games. If the GLSL renderer needs at least a GeForce 8600, then don't think in buying a card under 100$

[NiGHTMARE]

Actually, you can easily find an 8600 GT for under $100. It's definitely enough for GZDoom, and should work well enough with Half-life 2 and other games that are a similar age (or older), but it'll struggle with more recent games.

If you're interested in playing games like BioShock or Mass Effect, I'd recommend upping your budget a bit and getting something like the Radeon 4850 (which can be found for under $200). Don't pin your hopes up on running Crysis well even with that card, though .

[wildweasel]

I bought my GeForce 8800 512 MB for $200. It runs Crysis at a decent clip on medium details and 1280x1024.