I'm booting straight to XP, no bootcamp required. I tried running Amp, and while it's very functional for music, there's no turn by turn GPS, no sat rad support. I tried running Road Runner via both Parallels and VMWare Fusion, didn't work very well.
There are more frontend options for OSX now than there was a year ago. As far as I know there still isn't a viable turn by turn GPS option for OSX.