If you're not sure if you'll like flyfishing, borrow one or get a cheap one. All the box stores are selling full set-ups for under $100 now. But they're bulky 2-piece with crappy parts... just saw a buddy break one after just a couple hours of fishing fresh water recently.
The best all-around rod for the money in my opinion is the TFO Professional. A 6wt in 4 piece is small enough to carry easily and I've caught everything from Hill Country Bass to 26" Redfish on mine. For $149 and a lifetime warranty I've yet to find a better deal. And the feel and cast of this rod is truly top-notch even on the flats.
Pair it with a reel that can handle salt and has a light to heavy drag and you've got a very versatile rig. I like the Lamson Guru size 3 - so you can put more backing on it incase you hook a really big fish. I've not found a reel that can hold up to salt with such a nice drag for any less.
Good luck there's lots of good choices out there.