That was my understanding too. I'm glad to hear that only the wallet.dat file is what acts as the container for the "crown jewels" and that it is as simple as keeping that file well protected. Will test it out to confirm for myself that all works as described in this thread.
Thanks everyone for your questions/input.
Please share your results. Thanks.
Worked as expected. I created two wallet.dat files with different public/private keys stored in them and swapped them around at will. Main thing was to shutdown Bitcoin-Qt first, then swap the files, then start it up again.
Some other stuff I tested on two different machines (both OS X running 0.8.0 (haven't upgraded to 0.8.1 yet):
Downloaded entire blockchain on machine A and created a wallet on it too. Installed Bitcoin-Qt on machine B but DID NOT start it up. Instead I first copied the whole data directory (~/Library/Application Support/Bitcoin) from A to B. Then booted it up on B and it synced the last couple of blocks and was up and running nicely without having to sync the whole blockchain from scratch (and the keys from my wallet where there too). So was easy to port everything over to another machine and be up and running quickly.