According to some fairly major testing by 802.11 vendors, Bluetooth can kill 802.11 networks in some situations, mainly due to the fact that it has a much higher response speed so it can grab any empty airtime.

I have played with Bluetooth and 802.11 a bit and don't notice much effect. As yet I have not seen any Bluetooth product that I rate as worth the price, although I like the idea of a Bluetooth hands-free kit for the car, so I can leave the phone in my pocket and it'll just work.

My tuppence worth - the Nokia 6210i is pretty solid, tri-band, GPRS, very fast interface, voice recognition, withstands multiple drops to concrete and being run over, but admittedly it gets upset when dropped into a tank of diesel and not retrieved for 2 days

But then I don't like any non-Nokia phones, they all have issues I can't put up with: the slowww t68i, fiddly brakable Siemens, odd Motorola interface etc etc etc