I have updated my OS X Install and Customize Tips to include compatibilities with 10.1. Some hacks will not work on the new version, and in several cases, one needs to reapply tips. The modification for multiple icon sizes fails on 10.1 and I am yet looking to re-hack it. Meanwhile, the added notes on 10.1 should be read if you plan to upgrade.
[Editor's note: This is a very nicely done page with detailed explanations of many useful OS X hacks and tips that should be considered during installation and setup. Well worth a visit...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011014045130701