I would get a bluegears b-Enspirer sound card for $109. They are amazing. I have one and my brother has one. They win a lot of award from reviewing companies and they are very high quality cards.
I would get 2x1GB of G. Skill DDR2-800 (HZ; with the black heatspreaders) for $105 after Instant Rebate at newegg.
As far as Vista goes, if you just want a Vista operating system that functions properly I would get Windows: Vista - Home Premium. If you want every little gadge and widget I would go with Ultimate. (Comparison
I would get a Tuniq Tower 120 or Thermalright Ultra-120 eXtreme CPU Cooler + Arctic Silver 5 Thermal Compound. That will set you back $100 shipped and at your door. Leaving you money for a Mouse, Keyboard, Fan Controller, Fans, Mouse Pad; stuff like that. Fans: what do you want, silence, perfromance, or a balance?