I threw on my finest Canadian tuxedo this weekend for a stroll through the city with a girlfriend...
I found this vintage Levi's jacket last year on eBay and I can't seem to stop wearing it. It's so comfy and broken in from years of wear by its previous owner. They just don't make denim quite like they used to - vintage denim just feels more substantial, comes in better washes, and has a much more interesting fit.
Most of my vintage denim I've found in thrift stores, eBay, or flea markets but there are also many online retailers carrying vintage 501's - like Urban and Nasty Gal. Count on having to get most vintage denim tailored to fit you because that's when it will become your favorite thing to wear :)
For more info on sources and where to buy, see links below!