I know it's a continual refrain on this part of the board, and I apologise in advance....but, get a Mac!
Powerbook G4 with built in Bluetooth and a Sony Ericsson V800 (one of the Voda-3G handsets) talk perfectly....even though they're not officially supported...I can sync with Address Book, Calendar and surf a 300kbps connection with no problems at all. Setup was an absolute breeze.
(However, my mother with her Sony Vaio and Ericsson T39m has nothing but trouble....that's what happens with using 3rd party software....with Apple, it's built into the OS.)