I've been wanting to do some GPU programming for quite some time, and tried to take a step in the right direction. I picked up a fairly inexpensive nVidia 7300GS card for my HP Pavilion a1310n, thinking that would be a good way to get started, but when I use the binary drivers that nVidia supplies, I get lock ups every few minutes when using any GPU accelerated functionality. Grumble. Some indications on the web seem to be that the particular chipset on the ASUS motherboard that lies within could be the culprit: many other people using similar 6600 or 6200 based cards appear to be having similar difficulties. Sigh. I guess this board will be going back.
In the mean time, I found that the Wikipedia has a nice table which tells you what the differences between all those nVidia GPUs are. Useful!