Decided to sell, what to buy?

I hate to start a "what should I buy thread" but I unexpectedly decided to upgrade this week. While browsing ebay I realised that FX60s are going for $400, the OCZ Ram I have is going for $100, and I'm sure I can get $50-$80 for my motherboard. Assuming I can get that value for my parts it would be stupid for me not to sell and rebuild (CPU, motherboard, and RAM). However since I wasn't planning on upgrading for a while I've been kind of ignorant of such hardware over the past 6 months. I'm looking for high performance and good upgradability. I was going to step up my 8800GTS to a 9800 and was willing to spend another $300 but after looking at the 9800 offerings I've changed my mind so part of that $300 can go towards this upgrade. I'm figuring best case scenario is that I get $600 for my old CPU, MOBO and RAM and worst case is $400. Assuming I add another $150 - $200 to that what set up would offer the best performance know and best upgrade path? Thanks in advance to any opinions.