I would say white will look cleanist longer just goes gray like white vans

but i think white is now far too common and much more so than black at this time. I also like the black better as it gives it a more upmarket look. It also stops people thinking you simply bought another white good.

From your other thread,
My personal choice if i was re-ordering today after seeing loads and loads and loads of GTIs and mk6 golfs my personal colour choice would be between
Black pearl (looks great but pain to keep clean, but to me makes the car look classy and upmarket)
Red (not a colour i would normally go for but i think it really really works on the mk6 for some reason, and its easy to look after)
Graphite blue. (a colour that after looking out of my works window for a month has really grown on me the way it changes colour. Its sort of inbetween the black and red for looking after, and maybe looks a bit more expensive than the red, also its different and thats another reason i like it)