I have an HP Pavillion Slimline s7600n with an NViDIA Geforce 6150 LE, which is a fair chip, and a motherboard GPU, so it can't be replaced, but I want a new graphics card, because this one just isn't good enough for most new games.
I've already found out, trying to update this computer, that there is only one regular PCI slot, where most good graphics cards need PCI express or some AGP, so in the 2 1/2 years of having this computer, I have not been able to upgrade the GPU. Yesterday, however, I found out that there is a company called Jaton which takes fairly high end cards and makes them into low profile (half height) PCI cards, which is exactly what I need, so I'm going to be getting an NViDIA Geforce 9500 GT with 1 GB OF VIDEO RAM. That's just fucking amazing man, and it goes in a regular half height PCI slot. And did I mention the card costs under $100?

Also, my current computer specs, for anyone who wants to know them:
AMD Athlon 64 X2 3800+ Dual core processor @ 2.00 ghz, although it often goes to 2.20 ghz
NViDIA Geforce 6150 LE with 256 MB shared system memory
2 GB Kingston DDR2 800 mhz RAM
16x DVD Burnerr with Lightscribe technology
ASUS A8N-BR motherboard
5 USB ports
1 Firewire port
9-in-1 media card reader
1 VGA
1 SP/DIF
1 Wi-Fi
Integrated 8 channel audio
2 PS/2
1 Gigabit ethernet
AwardBIOS