I would also add to the list that an older boat with FEWER systems that work well, is better than the same boat that is loaded up with obsolete or non-functional equipment. Examples are CRT Radar, Loran, Water Maker, Electric Windlasses, Refrigeration.
I saw a lot of boats with broken autopilots, wind generators, non-functional wind instruments, gaping holes cut in a locker to mount the Radar CRT, yet the owners asked for top dollar.
These are both very good points to keep in mind as you look. I would also reiterate that a boat with new electronics and systems is worth only a pittance more than one without.
The great thing about the current market is that a boat that has been moderately refitted will not sell for much, if anything more, than an original boat in the same condition
The only thing that can justifiably inflate one boat's sale price over a comparable boat right now would be a VERY recent (as in last 5 years) repower.
Don't let the material cost of systems fool you. Anyone can install an expensive chartplotter. Most of the cost of boat maintenance comes from time. Either this is billed by the yard or it is your time stuck on the hard and not cruising. Look for boats that have had the big jobs done. Every model has common problems. Find out what they are and see if they have been addressed.
Things like a redone bottom or keel repair, recored and refinished decks, and new standing rigging, are examples of common jobs on older boats that are infinitely expensive in time. Ask how the job was done so you know if it was done right.
If you are not on a deadline, be patient. The right boat is out there, but only you can know when you've found her!