Geez some of the replies were humorous but not very accurate.
A bike should look what is acceptable for being nice to the rider, be it black tape, some color tape, or even white tape which is the worse for showing dirt, but I have a couple of bikes with white tape and no issues with dirt as long as I clean it more than black tape. I use all sorts of brands and types from synthetic to cork and have always had success with 409, a friend of mine uses Mr Clean Magic Eraser pads with great results, I've also heard that whitewall tire cleaner works very well. I would not use Simple Green because it can actually stain the likes of cork and some synthetics to take on a pale green hue which would look very odd with white tape.
If the tape is cleaned regularly there is no need to replace the tape frequently, I have an 85 bike with the ORIGINAL white vinyl bar tape and hoods in very white condition, I have another bike with white Fizik Microtex tape that is now 4 seasons old on my main bike and it too is in very white condition.
What folk don't realize is that by not cleaning your black tape because dirt doesn't show nonsense means that your gloves get filthy quicker. I've always cleaned my black tape just as frequently as my other tapes so my gloves don't have to get washed as much which makes them last longer. I wash my gloves about every 10th ride, and most of the time they don't even need it.