"Best" is relative
There are a lot of 25 foot boats out there, many can be had for $5000 to $9000. It would be easier to make recommendations if we knew more about your intended uses. Daysail or cruise? Need good cooking facilities? Standing headroom? Since you are in Westport, I am assuming you will be sailing in Long Island Sound; but do you want to trailer the boat? I don't get the connection between single handing and the type of keel, so maybe you could expand a bit on that too. In any case, the "best" 25 footer is relative to what you will use it for. Regardless, I think the best "cheap" (one of your stated goals) all-around 25 footer is the Catalina 25 (pop top model). You can get one in good shape that is about 20-25 years old for less than $10,000. I prefer the dinette layout option below, although many were built with the table on the centerline. Standing headroom with the pop-top, decent galley, good sized cockpit, supported by a manufacturer that is still in business, active owner's association, nice sailer; an excellent value. Available in fin keel (my preference) or swing keel models. A close second: the Oday 25. No pop top, but the galley slides out of the way under the cockpit seats, leaving a wide open cabin. In contrast to the Catalina, the Oday has a stub keel/centerboard configuration. I think this is the best of both worlds: encapsulated, protected ballast, very shallow draft with the board up, and good sailing qualities with the board down. Unlike the Catalina swing keels (where the ballast is actually in the swinging part of the keel), the Oday centerboard is "light" and is controlled with just a pendent line; no winches, no sweating, no problem. And a big plus for the Admiral: the head on the Oday is behind an actual door. In the Catalina, its behind a folding screen. The Oday has the added advantage of usually being less expensive (all other things being equal). You mention Columbia as an option. Any Columbia is bound to be an older boat, with all that entails. They are pretty, but even fiberglass ages, and the older the boat, the more that will need replacing. There are many owners who take great care of their boats, replacing and maintaing equipment as they age. However, in my humble experience, this happens less frequently on the less expensive (smaller) models. Be careful with old, small boats as they frequently suffer from what I will charitably call deferred maintenance. I am not that familar with the Columbia line of boats, but I do know that the Columbia 24 was a full keel model. LIS is known for its light winds, and I would shy away from full keel boats for that reason. I know there was a Columbia 26 (more than one flavor too I think), but I can't recall ever hearing about a 25 footer. With more info on your preferences, maybe someone can give you some better guidance. One general piece of advice: when buying a smaller boat, all future purchases and expenses will be an inordinately high percentage of the intial purchase price (you may spend as much on new sails as on the boat itself, and just try buying new interior cushions!). Because of this, the initial condition of the boat should be very high on your list of priorities. Good luck!
