Enchanting and tailoring most of all, because they're so darned expensive to level up. Blacksmithing and mining is easy, just go into n00bie areas like Goldshire and farm the copper mines for mining and beasts for skinning, herbs aywhere for herbalism, etc. Tailoring is like all about high level expensive (500+g) patterns that make BOP items that take another 500+g to make. Hate it!!!
Enchanting is worse though cuz you rely on crummy green drops and AH if you start it at level 30+, since you can't make any low lvl mats from green item drops at that 30+.