I think that the question is too vague. Any boat is worth restoration if the end product meets the owner's needs and budget. The rest is just a matter of scale. There are "good" boats and "bad"; SailNet has lots of threads extolling the virtues and deficiencies of many brands. While I agree with BarryL about the virtues of Sabres and their chainplate issues, the list could be expanded greatly.
Sabre 38 "Victoria"