Excellent thread topic!
I am not a huge snare guy, but if I were adding to my collection and had unlimited funds, I would look for:
Any Brady snare
Any Craviotto Snare
Some marquee name stave or solid shell snares
Stanton Moore Signature
Ludwig Black Beauty (any era)
Ludwig Super Sensitive (any era, particularly hammered brass)
Ludwig Supraphonic (any era)
As far as the snares I own, I love all of them! I have two B/O Badge Acrolites that are great, and I have a Ludwig Black/White badge 5.5" x 14" Copper that is one of my favorites too. I also really dig my Pearl 5" x 14" Sensitone (a more affordable version of a Supra, in my opinion).