I've seen some really nice looking Android home screen set-ups, but plenty of them are on "rooted" devices or are running some community ROM. The following images are screenshots from my Haipad M701-R tablet - it is unrooted and not hacked, so these mods could be done by anyone on probably any 2.x Android device. I'll start off with the default Homescreen, the only thing I did was change the wallpaper.
LauncherPro is probably the most popular launcher replacement app on the Android Market. I'm using the "free" edition, there is a paid version with more features. The following screenshots are LaunchPro with BattStatt battery status monitor and Digital Clock Widget by Maize:
If you don't like LauncherPro, or don't feel you have a need for it's many settings or themes, you might want to try out Zeam. Zeam is a lightweight launcher alternative. It doesn't offer multiple docks or the ability to use custom icons or themes, but it's very responsive and doesn't require much overhead. Here are screenshots of it with BattStatt and TypoClock:
Both Zeam and LauncherPro are in the Android Market, as is BattStatt (all free). The Digital Clock Widget by Maize used to be there, but I couldn't find it through that software channel so you may have to look for a web download or another app store for it. TypoClock also didn't seem to be in the official market so I got that via my web browser (hint: Google "TypoClock.apk download"). Both BattStat and Digital Clock Widget can be adjusted between 1x1, 1x2, and 1x4 configurations (if you want you can put them alongside each other so they look like one widget). TypoClock is less configurable - it will only sit in the middle of the screen. I didn't use it with LaunchPro because, for some reason, the bottom of the text gets cut off in landscape mode.
Of course you can use whatever wallpaper you want, and both LauncherPro and Zeam work with Live Wallpapers.