I like pretty much all parrot species. I have no desire to own one of the huge ones like a macaw or cockatoo, but I'm sure they can be very nice birds. I plan on getting an African Grey at some point in the future but anything larger than that just doesn't appeal to me.
Actually, now that I think about it, I don't really care for cockatiels. Based on my experiences with them they just don't seem as intelligent or interesting as other parrot species.