Yeah it's a slightly silly question, but I overheard a couple of older guys discussing it at length at the kayak shop not long ago, was curious as to what ppl here thought.
'It' boat simply means the generally-regarded creme de la creme (our Lexus or Porsche), though obviously it's more about individual needs/preferences.
Their consensus seemed to be the Nordkapp was the 'It' boat 'back in the day', then the Explorer, then for a few years it was the Cetus, and now it's either the Xplore (Tiderace) or the Nordlow.
I've only been in the sport a fairly short time, so I can't comment on what paddlers thought 'back in the day'. Any old farts wanna speak up?