Win 7 - Multiple default printers
With Win 7, you can now specify different default printers based on your current network. See the figure below that shows how this can be configured.
The earlier problem with Word was happening due to the specific printer not being available. Since I can now configure different default printers based on the network I am on, the issue of not finding printer will not arise.
The issue of printer could possibly also get addressed with Office 2010 as well. I had played around a bit with Office 2010, but more with Outlook 2010. What ever little I used this technology preview bits, I didn't see this printer related problem.