Customize with Conky
A while back, I started playing around with conky. It's a really cool piece of software that lets you do some truly amazing things. It ties in tightly with lua, so if you're familiar with it, you're already a step ahead of me.
conky lets you add all sorts of information to your desktop. You can add processor monitors, heat monitors, uptime, disk utilization, network activity, the works. I'm not really particularly good at it, and I can still cobble something together that looks pretty nice (imho).
If you've got a couple minutes of free time and you really want to add some pop to your desktop, I'd suggest hitting The Google and digging up some information on conky. You'll be happy that you did.