If I had $80k to buy a nice weekend car, I would have the following criteria:
powerful, and fun.
Why those criteria? Simple. Those put a smile on my face. When I step into my weekend car I want to be having fun. If the car is flashy that's a nice byproduct. But I'll have fun whenever I put the foot down and hear that throttle blip and that nice raspy downshift.
A lot of the people here have stated some nice cars. But I would actually want something not too flashy. Something subtle yet a sleeper. My choice would be the 2013 BMW M5. I know it's a little bit over $80k but maybe in a year or two or used, price will go down.
Why? It's refined and comfortable to drive in. Maintenance is not a bitch, it's not too flashy and poser. But it has to be in Frozen Blue.