[saratogacx]

At launch you had 3 themes (blue, green, and silver) as well as classic where you had all the customization of Win2k's settings. Later on (SP3-ish) you got a zone orange/dark theme which was nice.

To do more you either used WindowBlinds or just grabbed a patched UxTheme32.dll which would accept unsigned theme files. Once you did that you had an almost silly number of options to try out from various web sites.