I'm suddenly a big fan of Ubuntu. The standard Debian installation never really worked well for me on the desktop (though it's great on a server) - sound wasn't working, there were too many packages installed by default (both Gnome and KDE), and the whole thing felt cluttered and fragile, taking too long to configure to a usable state.
Eerily, almost everything I was trying to do to that Debian installation is part of the default setup of Ubuntu. There are no desktop icons; there's a carefully considered collection of default applications: Gnome only, including OpenOffice, Gimp, Firefox, Evolution, Rhythmbox and Gaim; all my hardware was detected automatically, and the Gnome 2.8 desktop is wonderfully easy to configure and use (as is the Synaptic package manager that allows you to install extra packages).
Some notes: my Netgear WG311 v2 wireless card uses the acx111 drivers (acx_pci), which were installed ok but don't support WEP encryption, so is unusable (though it should work with ndiswrapper and the Windows drivers, hopefully). The CD and DVD drives are detected the wrong way round (the CD drive is /dev/dvd and vice versa). You have to install ntp-simple to be able to sync the clock with an internet time server. BloGTK doesn't do RSD to auto-detect API addresses. There's no way to disable 'paranoia' setting to speed up CD ripping in Sound Juicer. Rhythmbox doesn't play audio CDs or MP3s. Numlock is off by default. Firefox doesn't focus the cursor in the address bar in new windows and adds bookmarks to the toolbar folder by default (though it is only v0.93). The 'headphones' volume is set to zero by default, so I thought sound wasn't working for a long time. The desktop doesn't use the keyboard layout set during installation. Installing Flash and Java plugins for Firefox is difficult (because they're not free software).
I disabled the CD repository and enabled the 'universe' (debian testing) repository, then installed Inkscape, Nicotine, Java, Azureus, Mplayer, Muine, RealPlayer, Grip, gtkpod, puredata and BloGTK (which this is written in), and set up Firefox with Adblock and Tabbrowser extensions, Flash and Java plugins. It's running pretty smoothly, so far: certainly the closest Linux experience to OS X that I've had.