My dad bought an '84 Camaro Berlinetta -all black...and back then Ziebart was the big add on here in Iowa...they undercoated and sealed the hell out of that car. That car smelled like that undercoating all it's life, which oddly smelled of Crayons. Seriously: open a pack of crayons and that is what that car smelled like. Every time we go out to eat and the kids pop open a pack of crayons, I think of that '84 Camaro.
The other scent is Wendys. Every time I pass a Wendy's I recall my first girlfriend who worked at Wendys and always smelled of the place when we would "meet up" after work.