Any recommendations on round, u-boat or other styles that are best for salt?

Get the biggest pontoon type you can find.

There are several pictures of my *totally* rigged up ocean tube towards the bottom of this page:

Click any pic to make it bigger:

http://www.martialartsacademy.org/quietmanfish.htm

I have it all done up with fishfinder, GPS, etc. etc.
That model is a "Pioneer" I think, they sell them at Sportmart, it's the biggest I could find anywhere. Got it on sale for $65.

Of course that bad-boy is in upstairs part of my garage since i started kayaking...

Quietman

I have a Togiak that I use in the salt all the time. It is a V shaped and I think the V is very helpful when you have to puch through some surf to get out. It is very stable and kicks easy.

BB

Ya know, each style has it's strengths and weaknesses, but in the end they'll all get the job done. The round boats are good cause they're stable and they don't flex when going through waves/surf. U boats are good cause they're easy to get in/out of. V boats are good cause they're easier to kick. And pontoon style boats are good cause they keep you higher out of the water.

Drawbacks for the round boat is they're fairly slow and hard to kick. The U boats do seem to flex a lot (depending on model and design of course, V boats are usually in the more expensive category but seem to solve the flexy problem of U boats, and pontoon boats because of their high profile can get blown in the wind and put your center of gravity higher for beach launching.

I'll stick to my round tube because I like having the stability and security when surf launching. Unless you're going to be doing a lot of surf launches, it basically doesn't matter. Just find something with ample storage in your price range and go for it.
-Brian