I think, the answer is anything that has a little bit of heart to it. In the last 3-4 years, we have seen a tremendous amount of 'grassroots' companies, making snares, kits, and more. Believe it or not, there was as time when people didn't know or care who Craviotto was...now they do, because of the effort and heart he has put into his company.
I think it de-values the product & brand when companies put out 'limited editions', and they try to create a modern collectible. Example, and I love Ludwig, but are you truly telling me that there is no other drum in the world, that sounds like the anniversary versions of the snare drums they did a few years ago? That may be a 'player vs. collector' debate (for another time).
Finally, I think it has to be a product that isn't too definitive of the time. Couple examples- I saw a Gretsch 100th Anniversary kit, either blue or green with 24k gold hardware, 6 or 7 piece kit. The 10" tom was 9" deep, the 12" tom was 11 or 12" deep. Did the drums sound good, probably! Did they look cool...eh... once all set up, I think to an average eye, they would just look ANOTHER 80s kit. Something collectible has to have the hip or coolness factor- any museum or private collection will attest to this. Last example- the over sized bass drums. 80s and 90s I think the 20" and 22" depths run wild! As cool as they might be, they aren't a universal drum size. Also, new guys are getting custom built kits, thinking that these large sizes will be awesome- any given time, I can usually find 3 kits on C-list from Shine, Truth, etc. that have massive depths, that the seller can't give away!
So, to sum up- classic, timeless sizes. Timeless, usable voicing. Drums made in a country you value, trust, and respect. Drums made with some heart.