Thanks for your advice. I can now give some more specifics, since the most recent boat I am interested in has appeared on the web today for the first time:
1993 Catalina 28 Sail Boat For Sale - www.yachtworld.com
A few words about this boat. First, my wife has really gotten to like the Catalina boats. She has liked every one she has gotten on. There are a few brands of boats she has intensely disliked - don't want to offend anyone by mentioning them. Suffice it to say that one of them has a widespread bad reputation, and a couple others are well regarded as great sailing boats and built very sturdily, but the amenities are not as sleek as Catalina provides.
Don at Winters had told me this boat was coming a few weeks ago. The previous owner traded up to a C309 or 310 because they're getting older and wanted RF on the mainsail. His asking price is even higher than I thought he had told me before. I called him today to ask about it, and he said he could come down some, but not as far as my self-imposed price limit. (PM me if you you would like specific numbers.) I tried to steer the discussion to comparables, and Don emphasized that the boat is in exceptional condition and not comparable to others.
I know a lot of guys here don't think NADA means much, but I can't help use it as a guide because I know if I want to sell the boat the next buyer would beat me over the head with NADA's estimated values. NADA gives a retail range of $22-26k for the boat (even with accessories), which is right around my limit. It's hard to imagine even trying to get him to come down that far from a $40k asking price.
The C250 that I was previously considering sold over the weekend. No regrets - I had decided that we definitely want a 27 or 28 footer.
One piece of info would be very helpful - is there anyone here with access to soldboats.com who could run some comparables for me? In addition to sellers playing games with the numbers (like you warned) I am also concerned about sellers "cherry picking" their examples. I'd much rather have someone "on my side" pulling these numbers up for me.
PS - This C28 would be my "dream boat" - at the newest range of boat ages that I would consider. I am considering other older, much less expensive boats. I will post some questions about that other boat in another thread