I'd have a hard time narrowing it down to just three. I'd probably have to make a list and go from there, until I got it down to just three.
mid40's & up (to 53') Indian Chief, 42' Indian Four, 57' Indian (enfield) 700cc Apache, Norton Commando Fast Back, mid 60's Royal Enfield Interceptor, late 60's Jawa Californian, BSA 500cc Gold Star, BSA 650cc Super Rocket, Matchless 600cc Typhoon & an Ariel Square Four.
I think I could narrow them down to: 42' Indian Four, Royal Enfield Interceptor and the Jawa 350 Californian. I'd better quit before I change my mind.
Later on, Bill