I would agree that 1/700 is the way to go, particularly if you are just beginning, or giving ships your first shot.
Modern USN ships can be simple, or if you want to, can go for very tight detailing. Colors and painting are simple and an out of box build renders a model you can enjoy. Adding photo etch, etc., racks up the challenges very quickly, and gives you a real taste of the small scale, and what detailing can be done.
I'd stay away from a carrier as your first ship. The repetition of modeling all the aircraft, can drag out the build beyond the time you may be accustomed too, building other model types.
Working in 1/700 scale teaches you a few things about weathering. Techniques that work well on armor will overpower the smaller scale ship. Carriers, done right, require lots of weathering to get the flight deck looking right. Even in 1/700, a modern carrier flight deck is a "big" piece of plastic. Painting it all in one color just "doesn't look quite right." Working with smaller decks is a good way to "work up" to a carrier.
You are also well supplied with many good reference photos for modern USN ships too. The Navy's photo gallery at www.news.navy.mil has lots of good photos to help with any modern warship. That can save a little expense too. You'll need a book or two for a WW2 ship. Since you are just starting out, downloading free high res shots of a destroyer or cruiser is a big help.
You'll get lots of help here. Enjoy it.
Mike