It's a computer! Have a Cigar.
Turns out it's better than advertised. Not only does it have the glowing reviews mentioned in the first post, but Consumer Reports named the top compact desktop, though they said not to buy it because of technical support issues — of course I'm not going to get Linux technical support from HP, either, so that wasn't an issue. The computer also came with 6 GB of memory, more than the 4 originally offered. The only thing it didn't have was a 1 TB disk. The disk actually comes out as 931 GB, but you knew that was going to happen, didn't you?
Of course, it came with Windows 7. I turned it on, booted up 7, said
Ooh, shiny!, then went and downloaded the 64 bit version of Ubuntu 10.04. This installed easily, including all the disk partitioning — I left 7 on there, with 100GB of disk, because you never know. I played with the system for a week, and then spent yesterday consolidating all of the files from my old computer and my wife's computer (aka Hal and Hal's formerly evil twin) to the new box. I did have a few minor, and one not-so-minor, problems with the install, which I'll tell you about in the next few days. But, suffice it to say, after a week of using this machine I'm very happy with it.