I can't answer the question with just one glider. There are so many
beautiful designs to choose from.

Current generation of single seaters: ASG-29

Previous generation of single seaters: ASW-27

And the generation before that: ASW-20. Especially the WL version
with the 16.6m wingtips being hoisted up on the wire. Beautiful!

And the generation before that: LS1-c/d. You really didn't think I
would leave that out, did you? :-)

And here's where I need the first two volumes of Martin Simone's
trilogy on gliders, "Sailplanes 1920 - 1945" and "Sailplanes 1945 -
1965" to complement my volume "Sailplanes 1965 - 2000". But without
those reference books, I'll go with the OP's proposal and say
Minimoa. He's probably had one or two and knows what they look like
"in the flesh."

Ray Lovinggood
Carrboro, North Carolina, USA
PS: One of my favorites to see climbing in a thermal when I'm out
flying: Turkey Vulture, Cathartes aura