I'm just keeping track of some of the differences between kde and gnome in this blog. This will change over time. I realize that you can use a kde application in gnome and vice versa. Still...
*Default torrent client in KDE, ktorrent, is much more advanced than the default torrent in Gnome (transmission).
*No main system settings spot in Gnome.
*Amarok cannot organize podcasts by date, but rhythmbox can. Also, Amarok does not delete podcast entries.