I'd say Back to the Future's future was pretty darned awesome. And we've still got 6 years before we get there, so I wonder just how many things in the movie will have become a reality by our 2015?
Hoverboards: No. Not unless they have a maglev track under them or something.
Flying cars: Maybe in a prototype stage, but never practical for general use due to the hazards.
Mr. Fusion: No. Didn't make sense anyway. (Fusion fuel is hydrogen, not aluminum cans, banana peels, and the like. Unless it was actually a fusion torch of some sort, a hot plasma that vaporized those things and used the vapor as working fluid of some sort.)
Self-fastening/programmable clothes: Quite likely. We're already getting clothes and
jewelry with computer capability built in. If anything, the movie was too conservative; we'll have t-shirts with embedded video screens by then.
Window-shade TV: Perhaps not in that form, but given the development of flexible LED surfaces, we should definitely have video screens that can bend, fold, and roll up (see the t-shirt example above).
Free-floating holographic ads: Perhaps, to an extent. The sci-fi conceit of holograms in midair is rather fanciful, since any image needs something to reflect or emit light from, but there are some prototype devices that use a mist of vapor or microscopic particles as a sort of "screen" to project a 2D image into the air above them, and there's another prototype device that uses lasers to ionize the air into glowing "pixels" -- though that latter one would probably be kind of hazardous to get close to and probably would work better at night.
De-aging treatment: Probably not by 2015.
Then there are these articles:
http://www.11points.com/Movies/11_Predictions_That_Back_to_the_Future_Part_II_Got_Right
http://www.11points.com/Movies/11_Predictions_That_Back_to_the_Future_Part_II_Got_Wrong