It's not going to be as easy as just plugging your credit card into a form and buying a new TLD. There's a lengthy evaluation process to go through,
http://www.icann.org/topics/gtld-eva...ss-16jun08.pdf and at $50k each, I don't think we'll see too many spammers trying to take advantage of it.
Still, I see no reason ICANN think more TLD's are needed, except to line their own pockets of course.