my computer's an hp.
bought it in november 2004, and it's still working great.
The case it came in didn't allow for any customization, so i had to transplant everything into a new case to add multiple hard drives.
But it's almost 3 years old, already has SATA, pci express, and decently fast memory. So it was a fairly cutting-edge computer at the time, it's really still not that outdated technology wise, just getting slow.
But i've got it running xp pro, with 3 hard drives, running 603kB/s usenet downloads 24/7, hooked up to 3 monitors, and has given me 0 trouble in 2.5 years.
They're expensive, tho. HP's are the most expensive desktops on the market, spec for spec, but use very nice components.
For someone who doesn't want to bother building their own computer, and wants to be gauranteed problem free useage, they're worth the $.