Do you chase boats? Want to ride any sort of distance on this new hull? You are going to have to make some compromises if you want to flatwater/boat chase/surf as all 3 are different enough that there isn't really a hull that is 100% ideal for all 3 at once, other than maybe a T1. As someone else mentioned, super lightweight carbon hulls are what you want for flatwater freestyle, but not what you want for surf etc.
Superfreak Badass's and T1's seem to be the best hybrid hulls that do everything well. But with that said, i am leery of taking my Badass in the surf due to the light carbon build. But its the best boat chaser/freeride/freestyle hull I have ridden and that seems to be popular opinion. Glass -4.3 badasses are very good surf hulls but a little heavy to be a true flatwater hull.
If I was buying a dedicated flatwater hull with your budget I personally would go DVX > Phantom > Circus
If I was buying a "do it all" hybrid I would buy a superfreak (you wont find a T1 in your price range most likely, they are very rare still)
If i was buying a surf dedicated ski id prolly get a Rickter Edge or Glass Superfreak (this is just based off of reading, I have never rode surf so take this recommendation with a large dose of salt)