I don't like it for a couple of reasons (I won't name them all)
Banner: Pretty much sucks with that forum
Link Buttons(Home, Members, User CP etc.): Are larger than the bar next to it. Texting has crappy reflection effect on them (Reflection is ok, but not in the way it is done here). Texting has crappy font.
Icons: Some of the forum icons look messed up with the background, for example:
Blue: The type of blue used looks dull and boring.
Oh and there is also a bug if you go back from Black to normal. I have the normal background now, but all my buttons turned into the one from the black background.
Anyway, I did a quick mockup of how I think it would look better, I didn't do a banner, I just changed some colors to make it look nicer and less dull and I changed the navigation bar buttons:
Edit:
Here is one with a quickly made banner, as how I would think it should somewhat look. Note that it looks crappy because I couldn't find a good Earth render that quickly, and I had to cut out the logo from the website, that and I didn't want to recreate the entire top bar, so the 'glass' effect is not used on top of the banner.:
http://img210.imageshack.us/img210/5073/forummockup2co5.jpg