I was going to suggest a boot SSD, like the new Intel 40GB one. Whilst another 5850 is definitely a nice upgrade, I think an SSD would be working on the weakest aspect of your system. You'd keep it a bit more balanced.
If your budget could stretch to a 5870, it could also stretch to a 5850 AND an SSD.![]()
Dual monitors? Another of what you have if your happy with the first. Good excuse to put all the alcohol away out of sight so it doesn't tempt you to drink it!
I would upgrade alcohol to a fresh juice or avian water![]()