You can apply themes to change the status bar and status bar icons, and you can use an alternate launcher (Launcher Pro Plus, ADW) to change the appearance of the dock, and widgets will show the clock, date, and/or battery info as text.
once youre rooted and deodexed, you can use an app like rom manager to get a few, or find them online in forums like this one. you download them as a zip file and apply them in clockwork recovery.
besides that, its a combination of different launchers, customizing icons, widgets, a whole bunch of stuff. check out the post your screen thread that is stickied to this forum. if you see something cool, just ask the poster and theyll tell you what apps/widgets/theme they used
You don't have to be rooted to have creative home screens. You can dl Launcher Pro Plus and the Launcher Pro Icon Pack ... and that will give you an absolutely AMAZING choice of widgets and home screen layouts.
THEN, you should follow this same sticky thread about home screen customizations to find specific apps that give you what you prefer.
The X isn't like the BBs, where themes provided the variety in life. Rather, with the X and LP+, you can create your very own "look" that can change with your mood. Check out the thread ... you will be inspired!
The home screen you linked doesn't require root at all except for the black task bar. Otherwise it's just a couple of minimalist text widets for the time and battery percent, and Launcher Pro with custom task bar artwork (of which a ton is freely available on the Launcher Pro site).
For example, this was my how my phone looked last week (unrooted):
I had the task bar hidden at the time. This week I have a football-themed screen and a different task bar, but fundamentally it's the same setup (despite a very different look).