I've a got a white iPad 2 and use it a lot more for reading PDFs for Uni work than watching films etc. The white border just makes it look a lot more like your reading a piece a paper, blends in well when I'm also writing notes a on my A4 notepad.
So the whole argument that black is less distracting is wrong for my usage. It all comes down to what you use it for really. I guess black might be better for movies at night, but if you use your iPad during the day for documents, I'd say white is actually better.
Each to their own though! : )