Mmmmm... playdoh. Oh, yeah.
I went on a binge one time when I was around 4 y.o. and got really sick. Actually, now that I look back, it wasn't the actual playdoh that made me sick. It was whatever my mom had to give me to release it when it got "stuck in there". Still love the smell of it though.

the smell of...
Early morning breeze off the ocean
Orange blossoms
Fresh cut grass
Honeysuckle
Fresh brewed coffee (don't drink it though - hate the taste)
Steak sizzling on the grill
Wild mint tea on the edge of my yard
Strawberries