I don't usually change a lot on my desktops, so I always use these same settings:
Font: DejaVu Sans (Hint: Slight)
Icon theme: Faience
GTK themes: Zukitwo, Inverted, Glossy (with custom colors)
XFCE themes: All made by me :D
Emerald themes: All made by me :D
Other stuff: Conky, Audacious, Awn, CoverGloobus
Cheers :D