youll need to switch launchers. The phone comes loaded with Touchwiz, which is where all the colorful icons come from. the launcher is the "mechanism" they controls which icons and widget sets the phone uses, and also how the app drawer looks and works. the most popular downloadabe launcher is called LauncherPro, and its available from the market for free. Aftermarket launchers can be much faster and highly customizable. Once you installed your launcher of choice, then youll have to start finding replacement clocks and things like that.
The clock im using is called Bob3d, if you google it, it will take you to the thread on Xda of the guy who created the clock, and the weather stream at the bottom of mine is called minimalist text, which is also free from the market.
try out battstatt and tajim also, they are nice clean looking battery percentage and time widgets. hope this gives you some direction!