I think you should decide for yourself what color you want. I would prefer very black-darkbrown/entirely black, but maybe you would rather like to have some red or blond in your hair.
Personally, I only have experience with (semi/demi)-permanent dye, which my hairdresser always did, since I have blond hair. But brown hair is the best, since you can go both ways of the color spectrum without much risk of getting some nice colors like green and blue <img src="/images/graemlins/wink.gif" alt="" />
If you would like to do it yourself: make sure you read the instructions carefully and maybe ask a friend to help, since it will be not easy to color the back of your hair when it's your first time.