An interesting bluetooth possibility:
If you have a newer digital wireless phone from T-mobile, Sprint, etc. that has the bluetooth feature built in (only a few models) you can learn on the X1000forums how to dial into a college access number (if you are a student) or possibly even your own ISP dial-up # and surf the web from anywhere.
Bluetooth allows you to have the notebook receive the signal from the digital wireless phone with no direct connection.
Of course dial-up is not as fast as DSL or cable but when away from the house or the wi-fi access area at college, etc. it is an interesting possibility.
The other main uses seem to be synching between your PDA and the notebook (address book, files, etc.) and the wireless bluetooth option for an external mouse.
And, there are some bluetooth wireless headsets out there for the matching bluetooth enabled digital wireless phones so you could use these as well with your notebook (but this usage would be more limited than the other uses).