OCZ OCZ2T800C44GK 4 GB Memory $40 @ Amazon

The PC2-6400 Titanium 4GB Edition tackles your toughest computing experience, offering superior bandwidth and stability on the latest platforms. For enthusiasts shifting to Vista and who need the performance of high speed memory, the PC2-6400 Titanium 4GB kit is the ideal upgrade from the standard 2GB of RAM. The OCZ PC-6400 4GB Titanium series was developed to provide a superior computing experience that ensures the best possible gaming and productivity, and at incredible 4-4-4 timings offers tighter timings than typical 4GB kits. The PC2-6400 Titanium 4GB Edition will be available in 2048MB modules and 4GB (2x2048MB) dual channel kits. All modules are 100% hand-tested for quality assurance and compatibility and feature high quality, titanium-mirrored XTC (Xtreme Thermal Convection) heatspreaders for the most effective heat dissipation. Furthermore, each OCZ Titanium Edition memory module is backed by the industry leading OCZ Lifetime Warranty and technical support for unparalleled peace of mind.