Sparky, I think the BIGGEST boat you should buy would be a 53MY, at a stretch a 58. You will find plenty to keep you busy on a boat that big. They are very complex machines with lots of things on them that require regular maintenance. Ask anyone on this forum.
It sounds like you are going from very little boating to a pretty big boat to say the least. Essentially jumping into the deep end of the pool. That's fine, but be prepared to spend a lot of time reading manuals and learning how to run the boat, and yes you DO need a captain to instruct you- not just for a day or two, but for a few days a week for a month or so. You want to have fun, not scare yourself or hurt yourself.
If you just want to be on the water, and are not especially interested in going boating, a house is better. The good thing about a boat is that it moves. And boats that move regularly are healthier boats.