It's more or less inevitable that some manufacturer will create a handlebar or radio integrated device that will combine GPS, phone, mini-pc, MP3 player, & who knows what else. The Bluetooth capability of the 550 already does this (no pc) - figure there will be better versions eventually. Maybe it will even be voice activated like my Palm Treo phone.
Still like the Zumo 550 - know it will be hopelessly outdated in the next 2-5 years, but won't buy the brand spankin' new version until the price drops well below $1,000.
There are other GPS phones - mine could be adapted to be one unless I read the literature wrong. I have Google Maps bookmarked in it & that works ok. I have a couple of websites bookmarked that have color radar. New Nuvi phone looks ok - not for me.
The days when I rode a bike with no electronic stuff, etc. are getting farther & farther away.