Why now everything in black instead of the white/grey screen I am used and find nice to work in with photoshop. Black is very predominant when you are busy working on photographs.
Alt/Opt 2 will brighten the interface. Alt/Opt 1 will darken it again. I think the idea is to bring Photoshop's interface into line with Lightroom, and while mid grey has a nuetral affect on the images you are working on, a dark backgriund does tend to show them to better effect.
The darker interfaces are probably fine if you are producing images predominantly for Screen or Web Browser viewing but they are very misleading if your output is destined for Print and you will probably find that the printed output is much darker than you expected it to be.
I also find small text on darker interfaces very tiring and hard to read.
It will be fine just as long as the Creative Suites continue to give their Users a choice of Interface which the LightRoom team seem unable or unwilling to do.
Because of the design of LR's UI, I continue to avoid purchasing LR!
If you are not in favor of the new darker UI, you can change it to one of four schemes from dark to light that is available to you.
One of the lighter ones is very similar to the CS5 setting.
UI Color Theme can be changed in Preferences/Appearance
Please see the FAQ below for more details:
I hope that helps!