Could you share with us where you got that wallpaper? Thanks.
On GNOME, I will have to say that if I don't have the same good experience as in Ubuntu, then I'll revert to KDE immediately. GNOME in Ubuntu is so cohesive and rock solid in my opinion. So, I'm looking forward to the GNOME packages for Slackware 12 and try it out.
On Slackware being an "Expert Distro", that's exactly what I kept hearing when I first tried it back at version 7. I still went ahead and installed it. I don't regret having done it, then. I learned so much about Linux. It also came to me at a time when I was so bored with Windows that I soaked Linux in like a sponge.