Perhaps the single most significant evoloution in technology is the advent of GPS. It's not entirely new today (though it's still pretty darn neat), but it's rapidly evolving and it's use is constantly expanding. There are some fantastic developments on the near horizon with respect to avionics.
Personally, the advances that please me the most are the ones I see in the experimental field. General Aviation was on the ropes and nearly dead, with no more production of significance, waning interest, and a falling away. The introduction of new certificated airplanes was a massive shot in the arm; airplanes that were formerly kit airplanes in the experimental category. The introduction of a new generation of training airplanes at the grassroots level is ushering in a whole new generation of pilots.
Composites, period. Cutting edge 40 years ago, and still cutting edge today. Still rapidly evolving. Mindboggling potential.
The F-117 (okay, it's not new, but how the hell does it fly?). Still can't get used to looking at one, and will probably never get tired of the same.
Quieting technology. This is crucial to the future of aviation as urban sprawl increases, regulation grows faster than a rainforest, and entire breeds of airplanes are threatened with extinction unless they can be made quieter.
New engine technology. LASAR and other ignition advances in piston engines, GAMI injectors, and a renewed interest in tuned exhausts. Higher bypass engines that use less fuel, produce more thrust, fly higher, and are quieter, for turbofans. The Williams engine.
Lots of new and exciting stuff out there. Take your pick.
