Overdue for a new graphics card.

I have an AGP slot (NOT a PCI-E) and I'm looking for a 512 MB (my current card is a GeForce FX 5200 with 128 MB). My motherboard is an ASUS P4P800 if you need more information. Currently sporting a Pentium 4 2.40 GHz and a gig of RAM, and running XP. The main purpose for this upgrade will be gaming (surprise). I'm not going to spend more than $150 on this.

These are the two I'm looking at right now:

• Geforce 7600GT. (nVidia makes respectable cards, and this is reportedly the better-performing of the two by about 50%. My current card is also a GeForce.)
• HIS X1650Pro IceQ. (Cheaper, and the advanced fan feature sounds handy for SoCal in keeping the whole thing from overheating... though its effects may be exaggerated.)

If you have any advice on these two, or any I'm not considering but should, let me know. Also, if I shouldn't be prioritizing the graphics memory so much, or if it would be wiser to hold out and save for a PCI-E motherboard, I'd appreciate a heads up on that point as well.