I prefer KDE as windowmanager and KDE applications work best in KDE. For simple games however, I like the GNOME-games set. Everyone's taste is different but for me counts:
- GNOME-sudoku works better than KSudoku.
- GNOME-MahJongg looks *much* better than KMahjongg. I know this will change with KDE 4 but that's still equal to GNOME MahJongg and not better. I know I can (and do) change the tile-set and background, even download other images but with the GNOME version I'm happy to play with the default graphics.
- I like Robots