Definitely if it's your first bag, I WOULD say, BLACK would be a good purchase. I just bought the JUMBO flap and I like it a lot, as it holds a lot as compared to the medium sized one. Depending on your usage and purpose, you might want to go one size up. Again you can not go wrong with black.
I nearly purchased the white jumbo flap but realized that it was not practical for a daily bag and because I travel a lot, I AM sure the security belts would get my bag dirty when the security guys/gals take it out of the bin and onto the belt..