Personal power to the people!

To me, the greatest opportunities lie in those systems that have the possibility of altering the functioning of major societal systems by putting processing power in the hands of the citizen. 

In the same way that 'pull' will eventually win over 'push' advertising, consumers would flock to these solutions because they would not trigger 'big brother' fear, as would similar solutions that involve giving our information to a master database somewhere. 

The following 'killer apps' could be easily built in the near future, and would be affordable if produced in mass quantities.

Personal Doctor 

Due to the hassle and expense of visiting the doctor, one killer application would involve a computing device connected to an intelligent back-end database, which asks me some questions and gives a diagnosis. Humans could upon request economically review this finding at a central location (at least initially) who could then issue a prescription. An enhanced system would include diagnosis of blood and urine samples at home. Widespread adoption of such a solution would radically alter the health system. 

Personal Shopper 

A bar-code reader for my wireless handheld that would automatically tell me how much of a premium I would be paying for buying the item from a store; that would be another killer app. 

The system could automatically order the item from the lowest price trusted store and send it to my house. The system could also track my purchases, and automatically build a list of regular purchases that I need to buy, based on normal frequency or on use -- a 
matching reader could be placed in my kitchen and bathroom to record when an item is consumed. The list could even be automatically ordered. Widespread adoption would further pressure retail stores to be price-competitive. 

Personal Recorder 

This application, linked to the right devices, would be a nearly invisible, 360-degree recorder of sound and picture that could be hidden on one's person or in one's car to keep a constant record of everything happening. The recordings could be later used in a court of law, greatly reducing today's reliance on one person's word vs. another. An enhanced version would be searchable by date or keyword. A super version would be searchable by person, using face and/or voice pattern recognition. Widespread adoption would radically alter the legal system. 

Personal Guide 

Another killer application would be one leveraging positioning capabilities built in to my handheld which contains a global map, so that I always automatically have a map of wherever I am and the ability to calculate directions to get to anywhere else, by car or on foot. Linked to a yellow-pages database, it would enable me to quickly locate and call any business, as well as get directions there. Widespread adoption would alter the map and telephone directory industries. 

Personal Entertainer 

Another powerful idea would build on current digital video player capabilities by offering an intelligent entertainment system that would instantly and easily find schedule information on recorded video programs, predictably record in advance what I watch, suggest (accurately) similar programs or games, and at the same time eliminate advertising by matching visual and/or auditory patterns from a central database. 

The system would be even more powerful if it were to store audio information from CDs. An enhanced system would have a mobile unit which allows me to be entertained anywhere. Widespread adoption of such a system would destroy the value of commercial TV advertising yet enable on-demand purchase of encrypted audio and video programs. 

Once again, the key to success would be for the solutions to be client-based, not server-based, due to the fear of security. Of course, the transformational nature of these solutions would naturally lead to strong resistance from those that represent the status quo...