Your question is germane to me. We are currently in the process of buying a new boat, selling the old, and you know what one of the absolute criteria for the new boat was? It had to be smaller than our current boat.
We broke things down into how we intend to use the boat. Based on that, we created a list of needs and wants, and our goal became to find the SMALLEST boat possible that had everything on the list. Also, I've come to believe that displacement is a better measure of size than LOA is.
Our Formosa 41 is 50ft LOA with it's bowsprit, but I used to think "it was really only a 41." However, we weigh as much as most newer 50 footers due to our overbuilt hull construction, which means bigger masts and sails in order to get a decent SA/Displacement ratio. The bigger stuff means more expensive to maintain, just like a true 50 footer would be...
PBeezer's point can't be emphasized enough. Think about how you will use the boat, and from there, think about what features, design characteristics, and gear will help you use better succeed at using the boat the way you plan to use it.
Again in my example, my Formosa 41 is not a very good boat for the PNW, but it was bought to live aboard and be capable of going to Australia. Once in Australia, we planned to sell it before returning, because it is not suitable to us for cruising up here. Now, we think we may have found a boat that is more suitable for the kind of cruising we do up here, AND will take us to Australia. Since it's suitable for up here, we now can plan on bringing her back too... But our needs are specific, and very different from just about everyone else, so the boat that makes sense for us, won't make sense for someone else. Then, it was a matter of getting the smallest one that would do the trick so we'd have as little expense and maintenance as possible.
MedSailor