I believe the way I feel about my memory today (including "extended" memory) is very similar to what my 2 years old feels like about it.
I put a bunch of things there but I can't reach them when I need them. I probably don't even realize I need to reach it even, which is a much bigger problem.
What things need to change in order for my extended memory to feel mature again:
1. Physically. The memory storage needs to be available all the time from everywhere. This implies residing on the net for all my storage needs. I've been carrying my notebook everywhere for more than a decade now and I have a permanent internet connection (while in the US), but I'm kind of tired of that. Also, sometimes I don't want to open the notebook and wait for it to un-hibernate so a PDA came handy, specially when together with the phone meaning it's highly probably I will have it with me most of the relevant time. Even then, and assuming blue tooth synching it's one more device to carry around. Internet is the answer, I don't feel comfortable with internet email, but I'm thinking seriously about it ... I should try some x drive thing as well consistently ...
2. Programs. Then there's the software part of it. Associations are so poor in today's storage world. Basically you save files/documents/photos/source, etc, and you can just hope you can retrieve it with a simple text search. I tried google desktop search some time ago, I wasn't that impress with it. We need to link things, much like the autolink in google's toolbar (another example of browser evolution taken over by a plug-in), but happening more automatically in our whole storage base (today meaning windows desktop applications, or meaning we don't use those at all anymore) and suggesting many other links than maps, books and car VIN's. A lot more to elaborate on the software area.
3. Interfaces. The last component on accessing memory is how to communicate your needs and get your retrieves back. For now the standard keyboard is long away to die in my opinion. I tried to use a tablet pc couple years ago. It was an interesting experience to find out that as long as all our applications are designed to work with a keyboard: you need one!! Tired of carrying the tablet plus the keyboard I gave up on the tablet thing in less than 6 months (I really really tried ;). Keyboards will probably change becoming more an on and off thing. Interfaces could change to have more voice recognition (although I don't see much evolution on this side for some type of applications because of the lack of privacy and other issues) and possibly direct mind connection, there are nice experiments already done such as a paraplegic person already handling the mouse with their brain, very promising.
I'm most of the time thinking about 2, anybody could have guessed that :)