I just changed OS'es from Vista Home Basic 32 to Win 7 64 Bit

I have currently as Hardware

Mobo:  Abit KN9 SLI

CPU:    AMD Athlon 64 X2 Dual Core Processor 6000+ 3.00 ghz

RAM:    4 Gig (2x2gb) Crucial PC2-8500 DDR2

HDD:    Seagate SATA/300 Baracuda 3.5 IHD with 320 GB and 16 MB Cache (Single HD not raid setup) 

GCARD: Dual Nvidia 9800 GTX+ 512 in an SLI Configuration

SCARD: Soundblaster  X-Fi Gamer

Software wise I have only installed

Win 7 Home Premium 64 Bit

Lastest Drivers for my G and S cards

SC2 Beta

Impulse and E:WoM

So my question is what can I do to increase performance and power, preferably on the software and settings end to increase my rigs power? Though Hardware Upgrades for future consideration wouldn't be unappreciated either.