For the Gnome-impaired, a short explanation of the screenshot:
This is Ubuntu/Karmic with the default Gnome desktop minus the top/bottom panels, plus the "New Wave" theme. Font rendering is light hinted with subpixel AA (to non-Ubuntu distros: *this* is how fonts should look like by default). The panel on the left is AWN, which hosts the gnome menu, application launchers/buttons and applets. The tabbed window at the top is a plain Nautilus view; central window is an application launcher (invoked through cmd+space); the bottom window is a weather report hosted in AWN; the icon is a plain ftp connection that opens in Nautilus (right click to disconnect).
I'm not 100% happy with the side panel yet (this is a dev version of AWN, docky2 is even prettier but way more unstable/immature). I hope by the time of Lucid Lynx, either docky or AWN will have released a stable version.
The central app is gnome-do, which is one of the best applications to come out of the Gnome side the last few years. It completely changes the way you use your computer: no need to search through gnome-menu, kicker or whatever in order to launch an app. Just type the app's name and there it is! ("F" for Firefox, "E" for Evolution, etc etc - it automatically learns your shortcuts). Gnome-do or its underlying engine should become part of the core Gnome desktop (if only to see the die-hard trolls frothing against Mono or whatever ). This is version 0.8.2 which suffers from a few bugs (wrong font size for example), but it's otherwise running great.
In my opinion, *this* is how a desktop should look like: clean, uncluttered, providing clear focal points to the eye (unlike e.g. the tiny 8x8 pixel "logoff" icons to the far right of the KDE taskbar). The "New Wave" theme is understated, with dark colors, subtle gradients and strong visual cues. It does everything it can to get out of your way, while providing feedback on every meaningful action: buttons light up on hover and depress strongly on clicks; close/maximize/minimize window icons are cleanly marked and light up beatifully on hover.
Compared to KDE/Oxygen, the latter gets half of this right. Oxygen also provides good visual feedback on hover/click events, but it's way too bright, aggressive (the horizontal lines on window titlebars are positively abrasive to the eye) and lacks good focal points (dolphin windows are cluttered with icons and panels and lack any depth. The taskbar suffers from the same issue).
This is not meant as trolling or "my desktop is better than yours", just some constructive criticism by someone who loves good UI design. It would be great if someone with a highly customized KDE 4.x desktop could provide some screenshots/feedback/hints on what, why and how he has customized his.