Unfortunately MS took the Katy off the market several years ago - though some retailers' ads say they have it in stock. (I'd call first.)
The Model Shipways Phantom is a beautiful ship and a good one for newcomers - if you like solid hulls. Same goes for the Bluejacket Mary Taylor. MS seems to be getting away from solid hull kits; there are only three left in the catalog - and two of those are marked "out of stock."
If you want to jump in with a plank-on-bulkhead kit, I haven't built any of them so I don't know just what to recommend. Here's the link to the Model Shipways POB page: http://www.modelexpo-online.com/search.asp?SKW=cat1_SW%20cat2_b0 . I strongly recommend starting with a small ship on a large scale. The road to success in modeling is paved with Constitution and Flying Fish kits that beginners have bought and abandoned.
And Pawel is right: for heaven's sake stay away from the HECEPOBs - the kits by Mamoli, Corel, Artesina Latina (aka Artist in the Latrine), etc.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.