I have been learning Ubuntu paving my way to learn Linux at command line. That latest 7.10 doesn't really impress me at the GUI so I also tried Mandriva 8 and Fedora 8. The KDE desktop is better, I think, so I should just switch to Kubuntu.
I'm a bit disappointed at Mandriva and Fedora GUI design when I tried installing them into my harddisk. If you aren't geeks in Linux yet or don't bother reading long documentation while installing then don't try. Obviously one would be concerned if the Windows partition would be destroyed by a wrong click.
At the end I went back to Ubuntu 7.10, updated it, and found that there were recently improvements on installing Adobe flash and Java SE plugins for Firefox. I was delighted because these were the things that I felt necessary for people switching from Windows. If software/feature installations are further improved for no-brainer then Ubuntu will gain further popularity in no time.