In my time, I've tried Lindows/Linspire (OK, but no programming tools and I'd rather not pay for Click'n'Run stuff that's free with other distros), SuSE 9.1 Personal Edition (again, deficient in a lot of software - no wonder it's a free download now - not a good ad for their Professional Edition at all), Red Hat 7.X/8.X/9.X (nice once you've got used to them and pretty well the "standard" out there for several years w.r.t. third party software), Debian (horrid, horrid installer...but that was a couple of years ago - might have improved since then), Mandrake (OK, but no real advantage over RH/FC really), Slackware (horrible installer again), Solaris x86 (stopped half way through installer - can't handle extended partitions, making it useless) and Fedora Core (which I'm happy with - until FC2, still similar to RH 7/8/9).
One thing I've noticed is that some distros still amazingly persist in using lilo as a bootloader (which FC has marked as deprecated in FC1, FC2 and FC3, but hasn't had the guts to drop it yet). GRUB is so superior to lilo that I find it shameful that any recent distro would still use it - it's actually now become a showstopper for me for Linux distros - if I'm not given the option to use grub, I won't use the distro. You might find that fussy, but when I'm dealing with multi-distro installs on one hard disk, I do NOT want to have switch bootloaders to a clearly inferior one, just because a particular distro is still living in the mid-90's.