The problem with tattoos is that, like red dawn said, 99% of the people who have them are posers who are doing it because it happens to be the trend of the minute. Kinda like smoking. There's going to be a lot of money to be paid in the plastic surgery business in about 5 years when all of a sudden tattoos are suddenly gross and a symbol of low-class.
Put another way, if you want to lose the geek image, you can throw away the ipod. But if you want to lose the "i'm a dumbass" image in a few years, it's probably gonna cost a lot more than what it cost to get it in the first place.