Bryston amps — I'm super curious how they measure up against the Hypex stuff.
The classics against which so many things are compared: Rogers LS3/5a, JBL L100, Quad ESL 57, Vendersteen 2c series, Magnepans, etc. It would be super interesting to see how much they were a benchmark and how much of the love for them is mostly nostalgia.
Also any audiophile-internet-hype-of-the-moment stuff: Ascend Sierra, Tekton, etc. Really mostly because it's fun to see the new overhyped stuff torn apart (and to discover which ones really are giant killers).