My thoughts:
1- What is the goal of the default theme?
2- What themes would GH choose to offer... (I'm not sure that 'says' anything about GH)
DISCLAIMER: I use Nostalgia because I prefer dark screens, and I have a minimum 24" bright quality screen and white is often overpowering even when brightness is turned lower. I often am in a dark room at night (relaxing) and bright screens can be a bit too exciting
Deskthority is too bright for me.
If the goal is to "sell" GH and gain new members, and to use the default theme to initially attract and entice as a sales tool, what theme would do that best? A theme that is mainstream/common/fits like a glove, or a little different and stands out from the rest?
I did use Thoriated for quite a while, it is nice, but I prefer dark.
As far as newcomers, if you want them to click away happily, we need a GeekHack Girl (unfortunately my girlfriend won't even hear of it, so don't ask) in a GeekHack wet t-shirt, GeekHack ball cap, all in GeekHack colors.
These are my thoughts.