I have been trying out KDE 4.2 for the last couple of days. So far I am very impressed.
The oxygen widgets look good & generally the desktop looks very pretty even without Compiz (which i don't have enabled anyway).
IMO it's a huge improvement over 3.x (and the early 4.0 releases).
The Dolphin FM is also nice & so too is the default Wallpaper.
Three cheers for the KDE team.