How customizable can a mac be?

[1080ski]

i remember when i used to have a PC, you could pretty much change anything on it. i was wondering how much you can do with macs...

the bars that the computer has on top of most windows (finder, ect...) are sort of bland. how much can i change em up? what are some other cool things you can customize?

i know stuff like the pictures in the finder and the highlighting color, but thats it. im looking for something more though

 

[Xave]

The only way to really revamp your mac theme is through a haxy called Shapeshifter. Right now its not really supported by leopard (only some themes in beta, others not working at all) but here's the link anyway, in case they update it in the near future.

http://unsanity.com/haxies/shapeshifter

Warning though, this may fuck up your computer, as it's a haxy. Well, it's popular, so in conclusion I wouldn't really mind trusting this.