I don't own any of these so I'm mainly going off the top of my head, but I think perhaps the Fun Wand would have the greatest versatility. You have one side heavily textured, one side smooth. Curved enough for rocking, but not so extremely curved that thrusting would be difficult.
I own a few of these, and I voted for the Alumina Revolve; as much as I love nJoy, you asked about versatility. The Alumina line has the ability to switch ends between toys, so you can customize the toy for what you prefer. I combined my Revolve and my Flow and now have a toy I like more than either of the two alone.