Hopefully more unlocked phones will start coming into the market. The cool thing about this 'developer' version is that there is no checksum check built into the bootloader. With T-mobile subsidized phones your stuck using signed firmware images.....
Most of the Google oriented services can probably be replaced by other applications; I expect. Having a IMAP email client would be wonderful.. maybe something that can take a Exchange plugin from the OpenChange folks would make these phones a much more attractive item for business types.
Who knows. Android may be the first introduction to running a open source operating system that many people will run into.
Also you should be able to run Debian on one of these things, as well as run Android on the OpenMoko phone or the Nokia n810. Koolu, a Freerunner reseller, has a beta Android version that you can run on those phones.
Then there is a company in Australia that has a Android phone out on the market, which may be interesting.
Personally I am going to wait a bit. I just bought a Sony Ericson phone and in a couple months I'll probably be in the market for a smart phone to hack around with. This way I can use my SIM card from my current phone in my 'hacking' phone and thus have a escape route if I end up bricking something or don't have things working quite right.