I often find these two equally entertaining, but I'd have to say Rarity. It is too easy to depict a character like Rarity as... you know, a total bitch. But the creators have decided not to go down that road and I really appreciate that.

I love the heck outta Granny Smith; she's one awesome grandma, and was a beautiful filly (was she always called Granny Smith? *lol* It's a pretty good apple name, but of course it sounds elderly, and really fits now that she's a senior citizen!)...and not to MENTION how important she is to the entire history and settlement of Ponyville...but as for character preference, I guess she can't yet rival Miss Rarity...about whom I completely agree with Queencold!

I'm not a Granny Smith fan and I LOVE RARITY!