There are iSync plugins for pretty much every type of phone you can think of, so syncing isn't an option. Sometimes the plugins are provided by the manufacturer (Nokia provide it for a lot of their N series phones) and sometimes it's provided by somebody you'll find on the internet. Either way, support is there
Bluetooth is bluetooth, so you'll always be able to send and receive data.
And if you find a phone that supports mass storage mode when you connect it via USB (many do) you'll be able to drag and drop files onto and off of it no problem too
I change phones at least once every other month and I've not yet owned a phone that I can't use with my Macbook