for purely an everyday driven street car, i'd have to say turbo. under normal driving, i see the same or better gas mileage outta my ex compared to stock w/ bolt-ons. i even have a new fuel pump, fmu, etc... also, i beat a gs-r with a jrsc on the same boost i was running (6lbs at the time). i think it's cause i'm intercooled mainly...and a better driver possibly too. the badass factor of a turbo is so much more than with a supercharger, unless you have a muscle car v8 or something.
definitely turbo...there are a billion add-ons you can get to make your car more unique/fast/badass