|basically DDR3 memory is faster and better for gaming etc, than DDR2 memory.|
these r all decent cards: ASUS Nvidia GT 430 1GB DDR3. (300W psu)
Sparkle NVIDIA GeForce 9800GT 1GB GDDR3 Low Profile version
ati radeon 5570 ddr3 1gb (i can vouch for this i have 1, its decent)
ati radeon 6570 ddr3 1gb
As for PSU, Yes usually the higher the number, the better it is!