I've had a Western Digital 320 gb (WD3200AAKS) as my main drive for a while now, but with my ever growing steam library, I found it impossible to keep all the games I wanted installed at the same time. So I went out and bought a Western Digital 1 TB (WD10EZEX), which is running on my SATA 3gb Mobo.
I had 2 setups in mind but don't know which one will yield the best performance. Taking suggestions!
1 TB drive, with my OS, Steam games, all other applications, regular data
320 GB drive storage / backups
320 GB drive with my OS, all other applications, regular data
Your first setup is best. Not only will it be faster but it will be easier to manage and keep clean. I recommend a new windows install if you can, it will clean up your rig substantially. But you'd have to re-install most programs (there's a way to move the steam programs, though). But WD has Acronis True Image WD Edition Software
Also, on non-valve games (won't work on TF2, CS, that kind of stuff) you now get the option to create a library on separate drives, so if you have non-steam games you can move them all back and forth between the drives by backing up the data and re-installing the game. Valve games like TF2 have to remain in the primary steam install directory, but you can move some of the files TF2 uses (textures and stuff I think) using steam mover or MKLink if your familiar with that (what steam mover uses).