I just want to point out something ....... the onboard graphics will be limited, and the only way of getting anything better is with a PCI card (not PCIe) and even that would have to be low profile ........ this is the only real limitation I noticed in the specs.
True, Just18. But I have to admit that I have the 2.8 GHz version of that computer (this one is 3.0 GHz P4 HT), and despite the modest graphics onboard, the graphics card was properly recognized during installation, and I never had a problem with video. I even watched online videos with ease (although full screen vids were a bit choppy). I won't (can't) claim that it'll do Compiz, but then I never tried it either, since I'm not into all the flash and glitter that Compiz delivers.
I will recommend, however, upgrading the memory in the advertised computer to 1.5 or 2 GB RAM, minimally. Otherwise, even with a light desktop, you may be digging into swap quite a bit, causing a serious slowdown. My 2.8 GHz version has 1.5 GB RAM, and I was (until recently) using it to build the magazine every month with Scribus, running Phoenix.