A little over a year ago I asked a question on theblog, if Photoshop is ever going to get the UI brightness slider we see in Adobe's Encore, Premiere Pro, After Effects, Illustrator, and possibly others. From what I've been told, this feature is still not implemented (Or perhaps I've been misinformed?). Three versions on (CS3, CS4, CS5. CS2 keept it old school.), and a common feature in several Adobe products, Photoshop's engineers still haven't caught on. Why put it all the other products, and not in Photoshop? Even the freakin Photoshop Elements has a dark grey UI. Wonder why?
Just give us the option to change the brightness so each user can set it to their (and not your) liking.
The present thinking behind Photoshops interface lies in the concept of "neutral". This goes back to its history as primarily a Photographic manipulation tool. Any color for the interface that is not color neutral, and a midpoint tonally, is likely to distract users from making accurate color or tonal distinctions in their work.
Of course providing an option to change this is a perfectly viable Feature Request, but its not something that many professionals would wisely do.
Look on how the revamped tools icons of CS5 no resemble those of After Effects. Maybe are we halfway there...