I had my old xp desktop for 6 yrs and finally bit the bullet and went all out for a gaming desktop.
I decided to play it safe and purchase this build from ibuypower and I haven't had any issues at all so far.
Core i7 930 2.8GHz cpu
2xAti 5770 videocards running in Crossfire
Kingston 64GB SSD
WD 6gb SATA-3 1TB HDD
6GB DDR 1333MHz ram
850W corsair PSU
fancy gaming case with 6 ridiculous fans
card reader
dvd burner
Windows 7 64 bit.
This new pc simply flies, its insane. I installed WoW in 20 minutes (on my old desktop it took hours). Like others, win 7 loads up in 30 seconds and firefox is instant, on my old desktop ff would take like a minute or two to load up. I haven't done any audio editing of any kind, but when I do I imagine it'll be a breeze pulling up wav files to edit. I'm simply content getting sick fps in games.