I started with white with the Samsung Focus but switched to black and stayed that way up until about 2 weeks ago. Now I'm all white. I think the tile layout needs to be specific to the white background to make it work. Thankfully, the new background image option has made going white even easier. Plus, I think the rest of the OS looks better using the white theme.
For a brief period I was hooked on light+ cyan, before 8.1, it was typically dark + cyan, teal, yellow, and sometimes a random color.
Now I keep it dark, goes nicely with my wallpaper.
Because i have a black L1520 i use the black theme, it makes the Phone look like it's made out of one piece of black marble.
And of course it saves energy...