My lady's family are all in Melbourne and Sebastian. I love heading down there from Jax in the winter. 15 degree difference in water temps down there in the winter. Mebourne has a pretty cool vibe and stuff to do when it's flat. Nice little downtown area with some decent bars and restaraunts. Can't say that for Cocoa, not sure about Stuart either.
New Smyrna is beautiful, but the surf is pretty crowded around the inlet. Southern Daytona/Ponce is pretty nice and quiet when it's not bike week. There's good biker crank too if you wanna get out of your mind.