I would have to agree with Bill - depends on what your going to fish i.e. large bodies of water like TR and what $$ you have and what $$ you want to spend in the future on the "extras" that we always seem to need to get the fishing done.
I started with a gently used Nitro NX750 that was a great first boat that I was able to pay for and still have money for a few extras. After a couple of years I moved up to a larger boat (20') and am getting ready to trade again. In reality that size of boat is larger than what most of the waters around here call for - in our area a large lake is 750 - 1000 acres - but I travel to bodies the size of TR on a regular basis so the larger boat is what I want.
He made a comment about the motor - that would have to be the number one thing in a used boat that I would watch out for - if you can find a used one that meets your fishing needs make sure that it has some kind of warranty on it or get it to a trusted motor guy in your area, nothing robs you of the ability to buy rods, reels and lures more than the $$ that you have to put in a motor repair.
The next thing to take into account is what dealers are in your area that you can get to work on your boat in times of need - for example here in the Cornhusker state I would have to look long and hard to find a Legend dealer. Not that a good shop cant work on about any boat but it is like taking your Ford to a Chevy dealer for specialized work.
Best of luck on your hunt!
C4F