If anything I'll have to go with Lovechild and GNOME. Once you get used to it, nothing else matters, atleast as far as I'm concerned.

Even with the bugs, it's very nice working with GNOME.
Most everything else is "acceptable" or "good" but not really "killer." Honestly, I wouldn't really consider GNOME killer either, but it's probably the closest to it at this point.
Although I feel oddly naked without having vi and the rest of my GNU commandline tools when I'm in Windows. Notepad is just, yech.
The killer application for me will probably be when a foobar2000 workalike comes along for Linux/X.
Dashboard seems like a VERY cool project, or atleast will be once it gets off the ground.