Interesting first post.
Well SLI is never worth it, unless you play games on huge resolutions, such as 2560 x 1600 on a 30" LCD.
8600GT isn't worth it either, if you're looking to play games in DX10 mode. If you want to game in DX10, you should at least consider an 8800GTS. I know it's not in you're price range. Just get a 7900GS instead. It will offer more gaming performance, than an 8600GT.
Patriots are good memory. Specifically the Extreme Performance models, that come with a 4-4-4-12 timing.
If you want a fast hard drive, go for the Western Digital 750GB hard drive. It's only $20 more than those four smaller hard drives, you were going to RAID. It's on par with a Raptor's speed.