Like Joe said "so really its all about what you want from the car and what does and does not annoy you."
Streetable for me when I was 18 was a license plate. I used to street race with open cutouts, race fuel, 10.5x29.5 slicks, 4:30s, glass nose, one seat, no sound deadener, stock manual 10" drum brakes... It was hot, noisey, lumpy to ride in, hard to stop, and generally illegal as hell.
I'm 40 now. Now streetable for me is high test pump gas, the ability to carry people/person, able to have a conversation when cruising, and some sort of mileage. I never minded driving with slicks and no heater...lol. But passengers will. I still rarely use a radio either. I like the sounds the cars make. Plus, if I have a problem that causes other's harm or damage, I have a lot more to lose.