Well, picking a favorite is really hard.
Especially since I have a few toys on the way that I haven't played with yet. Currently, though, it's a tossup between my VixSkin Spur and my Ella.
As for the WORST toy I've had, that's easy. It was vibrating jelly dildo. It was way too big for me, (at least at the time - I might be able to use something that size now if I'm patient) so I couldn't insert it because of the pain. Plus, I just hated the way it smelled and the greasy sensation it left on my hands. I recently dissected it and stole the bullet from inside it.