What you can do depends on which Bluetooth protocols are supported on both devices. I've paired my N810 with a number of devices including my desktop and was able to get all to work. On my Desktop I had to install an ap to support obex ftp from the N810 to the Desktop. My Desktop is Ubuntu. Bluetooth is sometimes referred to as a PAN, Personal Area Network. Distance is limited to your immediate area.

PAN is a bluetooth profile for running IP over bluetooth.

Personally I use bluetooth to provide a radio link between various computers, carrying the Delay Tolerant Networking research group's Bundling Protocol (see RFC5050). The devices automagically detect each other and forward traffic towards its ultimate destination. The end to end path might include conveyance over Bluetooth, TCP/IP, AX.25 links using amateur radio equipment, and other assorted methods.

So, bluetooth is, in general, just another radio that you can do anything you like with.

All that I've mentioned I can currently do on my N800, and I expect my N900 will do it too, although the USB host issues might cramp my style a bit.

Hopefully I've broadened your horizons a little.

whenever i see a question like the OP, i am reminded of this:
http://www.frogdesign.com/case-study...s-concept.html

sadly, it never got of the drawing table, as marketing/people wants "one brick to rule them all"...

that and maybe also that companies love vertical integration, and must be dragged into any kind of true, open standard adherence...

I thought bluetooth replace ur white teeth.

One small step in the good direction is that the N900 media player is DLNA compatible, so it's able to "play nice" with other DLNA-conformant devices on your home network:

http://maemo.nokia.com/features/media-player/
http://www.dlna.org/

that may be, but such a feature is a faded afterimage of the bright future pondered in the frog design concept.

but then i guess media file sizes outstripped bluetooths ability to carry them, and the low low price on chips hoped for never matrialized, so it never got built into random devices...

i cant help wonder where we would have been if any digital camera came with a bluetooth radio...