Super Capacitors: instantly chargeable batteries would be really handy in about a million things, electric cars being most notable

Augmented Reality: If we get it right, it will obsolete/improve a whole bunch of stuff (laptops, books, phones, movie theaters come to mind)

Cloud computing: I don't mean avoiding the pain of buying servers, I mean the final ultimate realization of dumb terminal and central processing hub (combined with augmented reality and you've got an always-on computational extension of self with zero bulky hardware)

growing things with algae: Oil, steak, ears (likely in that order)

3D printers: I just want to have an infinite cheap supply of standard rectangular Lego blocks.

Further out:

Fusion, hopefully cold: water in, power out (and I suppose whatever elements we're short on at the moment) my physics gets a little shaky here but I think fusion up to Fe is energy positive so an unlimited supply of iron could turn into some interesting things.

Hole diggers: Bullet train from New York to Paris that falls to its destination (and of course climbs to decelerate the second half of the trip)