I finally installed Ubuntu (10.10) on one of my desktop systems and really like it. There are some issues with video and audio (seems cached and doesn't play at the right time) and it doesn't run my favorite software under WINE, so my Windows 7 box is used for things that don't run quite right.
Other than that, Ubuntu works for me on my HP desktop.
I built a server a few years ago and keep loading newer version of Fedora on it, but since Ubuntu worked so well on my desktop I thought I'd try 32 and 64 bit on the server. Neither worked. At first I thought it was a boot timing issue but think the motherboard may not be supported. So Fedora 14 is back on the server and it runs great.
Other than Ubuntu, what linux distros do you suggest for the desktop?