Very interesting subject, lots of related areas that I've wondered about but don't know how things currently work.

To start with, I thought that USGS was a partner in TerraServer, and that they were providing updated maps as they issued them. Is that not true? What year is the cutoff date (most recent year of maps included, with newer maps not included)?

On the aerial photo side, I thought we were waiting for them (TerraServer) to expand the coverage area of the more detailed series - is that still in the works?

To reinforce some of the earlier comments, yes the ability to annotate existing map images and then save them in our database for future use would be very valuable, possibly even more so than the abiliy to import from other sources. However, as someone else mentioned, currently I just use a lot of waypoints in those situations, and that works adequately (as long as I stay organized).

In regard to source of maps we'd like to import, my first preference would be a way to incorporate some of the paper maps I have, thus I guess just a generic image import capability. I have some highly detailed maps that I've drawn from blown up tracings of USGS maps and then added local knowledge - putting these on my handheld with tracking features activated would be awesome. I've never used a map calibration program so I don't know the alternatives, but it would be pretty easy to specifc gps coordinates for several points on the maps.

Second import source, if possible, would be Google Earth. They have detailed aerial photos for many of the nearby areas that I'm interested in. I'm a low-level subscriber there and currently I get some of the benefit by after-the-fact loading the tracks recorded in BCN. I kinda suspect that it won't be possible to download their info without big payments, and it's not worth big payments.

Third, if possible, would be updated road info. Here again I could benefit from an explanation of how the current world works. I've seen some pretty puny computing devices that claim to have complete US road data, and I've heard bits and pieces about a comprehensive database maintained by some source. It would be fabulous if we could choose to have that road data overlaid on whatever map data we have selected for viewing. Do the sources want to charge too much for this info, or is it too difficult given the PCs processing limitations to include this info?

Still and all, with all that said, the current BCN setup is already 90+% there for my purposes (wilderness canoeing and exploring; other offroad exploring in jeep; road driving for touristy purposes). More would be gravy and would be welcome, but thanks so much for what you've already provided.

I would like to echo many of the comments and perhaps add a few ideas.
I had looked everywhere for a decent application to geocache and navigate. I used beeline for months and loved it for geocaching but didn't like the limitations of not ever being able to load maps. I actually paid for a license for GPS Tuner before realizing that it was sooooo slow and crashed frequently that it was useless. 10 minutes to start up and another 10 if you want to load a map, even with all other programs stripped off of my Treo 700wx. I toiled with the many programs that require independent map calibration and determined that I don't have that kind of time or dedication.
I have been pleasantly surprised with BN, though it still needs some improvements.
As said before the aerial photos and topo data are too old. Maybe this is because the older maps are free but I would be willing to pay a little extra for updated information. My neighborhood doesn't even appear on the maps and it is three years old.
It appears that there is a common interest in road labeling. It would be nice to simply load some other proprietary data such as Garmin's city Navigator or TomTom's or Magellan's but I see the expense and lack of support not allowing this to happen. Isn't there something out there with street labels that could be used in conjunction with the topo and aerial maps?
Is it possible to tap and hold to select objects on the map screen rather than having to select it from the menu? This gets annoying after a while.

And last of all the ability to customize. Many of the other programs while farther from what I want had some good features. One of these is to be able to select from a list of possibilities for the navigation tab such as: DTG, TTG, BTG, current speed, average speed, max speed, total distance, altitude, stopped time, moving time, and many other useful options. While including all of these would be too much clutter and choosing certain ones are good for some situations and bad for others. It would be better to select 4-6 different ones that you could change by tapping.

Thanks to all for their contribution to this discussion. I can comment on some ideas and what is practical or likely. 

To expand BackCountry Navigator, we think in terms of

• What will capitalize on what is unique about the product. You can probably help me here.
• What will expand our target market to a multiple of what it is now.

Expanding map capability beyond the United States will probably bring in more customers than improving what is available to US users, but doing these things are not necessarily mutually exclusive.
 
One promising avenue is a standard for WMS (Web Mapping Servers). There is no centralized directory of them, so it is hard to tell what is available. But there are at least some layers provided by Nasa, some Canada Topo maps and soem aerial photography of Mexico.   

Few of them are "tiled" yet. Tiled servers will probably be better for downloads.

http://onearth.jpl.nasa.gov/tiled.html

Right now, the exploration of tiled internet sources is taking priority over importing/calibrating files from various formats.

The use of fee based data is not really on the table right now. BackCountry Navigator just does not have the volume to make that cost effective. Even if we passed the cost on to you, the customer, we'd lose money in administering that.

We may find some sources that have roads in the imagery, but as far as when BCN will provide routing and driving directions, probably never. We are not going to attempt to compete with established street map programs.