I trust this author for Windows tweaking:http://www.tweakguides.com/TGTC.html
His guide for Windows 7 is more of a manual, however, than a quick-and-dirty tweak guide. In my opinion, Windows 7 is quite good out-of-the-box and doesn't benefit as much from tweaking as XP did. Really, I think it's a good thing as installing and optimizing XP used to take me hours. YMMV.