As you may, or may not have noticed, you have the ability to select the theme of your choice in your User Control Panel! I've installed 7 themes on top of the two defaults that come with the board. I went for a range of looks cause if I just went by my tastes everything would probably be dark and gothy You change your theme by going into the User Control Panel (UCP button on the default theme), Board Preferences, My Board Style. You can also set your timezone and other good stuff in there.
Current options are:
Dark Fantasy - the grey and black dragon one from the free place
Dirtyboard - my personal favorite because it has a sketchbooky type look to it
K_Kitty - yes, I went there. It wasn't easy, I nearly barfed, but I went there.
Pinkie - given as y'all know I hate pink, can you guess why I chose this BEFORE you go look at it?
Celtic Dreams - the name says it all
Fae Forest - green and mystical, makes me think of stuff like Avatar
For those who are curious I've tested out each of these (yes, even K_kitty and Pinkie) to a certain extent and even made custom logos for most. Personally I use DirtyBoard for now.
So, what are YOU using?