I am very new to this myself, but the Backgrounds free app give you many choices of backgrounds. I think you can also use a picture stored on your phone to create a background as well.
The Weatherbug app (paid) gives you a neat looking clock. There are also several free apps that give you different clock appearances.
Look in this forum, just a couple of sections down from the general discussion section. There are soom pretty nice wallpapers there. In the market there are several nice clocks and weather Widgets. Some free and some paid. There are several home screen replacement apps there also.
Read all the reviews, all apps aren't made for the Droid, some will not work with it. You have 24hrs to try them out, you can return if you don't like it.
