Having adminned Linux professionally for a few years and played with it for an age before that (going back to kernel 1.2 days) I've settled on Xubuntu for my sitting-at computers. Works nicely on everything from an EeePC to this machine (8GB, quad core, RAID1), requires a minimum of faff to install and keep updated and avoids the Windows-alike bloat of a full GNOME/KDE environment. Debian on the servers. I had a job that involved maintaining a fleet of Gentoo boxes and that got old really quickly - the additional admin time involved just isn't worth it. FreeBSD is also worth considering for servers, but a bit of an effort for a desktop.
Having adminned Linux professionally for a few years and played with it for an age before that (going back to kernel 1.2 days) I've settled on Xubuntu for my sitting-at computers. Works nicely on everything from an EeePC to this machine (8GB, quad core, RAID1), requires a minimum of faff to install and keep updated and avoids the Windows-alike bloat of a full GNOME/KDE environment. Debian on the servers. I had a job that involved maintaining a fleet of Gentoo boxes and that got old really quickly - the additional admin time involved just isn't worth it. FreeBSD is also worth considering for servers, but a bit of an effort for a desktop.