I think the most obv answer is anything that taxes computing power now will become much more lightweight in the future. Things like noise reduction, reverbs, synths, that sort of thing will continue to forge ahead.
connectivity will increase as well so remote video serving and storage, remote mixing, iChat style mixing and cutting, cloud based sfx and music libraries, etc.
Interactivity will continue its rise, so wii and kinect style interfaces both for creation and playback of sounds will continue. Also, more and more mixes will happen at runtime outside of the videogame domain. People will be able to choose to mute dialogue and fx and just listen to the music, or vice versa. They'll be adding things and subtracting things from the tv mix because users will be more actively interacting with the content. This means more delivery of splits and reduced mix quality in the tv and internet world. TV and film may also go choose-your-adventure style, which means multiple mix versions to cover various user decisions.
speech synthesis and recognition will continue being perfected. At some point you'll just load in a script and just tweak computer voice inflections. Famous actors will be voice-modeled, and you'll use them like graphic designers use fonts.
budgets will go down or stay the same, expectations will continue to rise.
speaker technology will change and allow for more pinpoint placement of things either in a crowd of people or on the sonic stage. This will complicate mixing.
microphone technology will continue to evolve. mic arrays that extract point source material from dense sonic landscapes will come more into use.
Massive corporations will continue to consolidate and crush competition. Anyone that writes any software of use will be quickly consumed by Avid/Apple/Microsoft. Everything will continue to get cracked and distributed for free.
either that or none of that stuff will happen. :)