Get what you enjoy, and what projects make you drool.
I love recessives, so I have all of the possible types of hets I can out of those projects. Also, since they take longer, it makes more sense to start out with them. BUT you need to have some that are trustworthy to have. (MAKE SURE YOU BUY FROM SOMEONE REPUTABLE)
With that being said, most people go with what they can see.
Get what you like. :) Bottom line