Decode the human genome.
Run the SETI project.
I've been doing a little video editing and my computer has been handling everything I've thrown at it so far quite well. I've also started experimenting with building a web page though I don't think that will ever be seriously taxing, please correct me if I'm mistaken there. My question is, "What can powerful gaming computers be used for besides just gaming and video editing?"
Here's the specs:
XP Pro 32 bit (thinking of upgrading to 64 bit later)
Intel Core 2 Duo 2.66Ghz (will upgrade to quad core this September)
8GB 800Mhz RAM (already have the ram for 64 bit os)
EVGA Geforce 8800GTX