A great deal has already been written about the HTC Magic Android Google phone. So I'll just add a couple of comments.
The inbuilt GPS receiver links to Google Maps, not to a fully fledged navigation system. Personally I prefer to see a map rather than a voice telling me where it thinks I should go, but that is another matter. Nor is there a route planner or all the other trappings of a GPS navigator. But I can live without.
More to the point, the map data is accessed online, either over the G3 network, or by wifi. There is no way (or no easy way) of adding your own data from a Navigon or other CD, or even downloading portions of google maps for offline use. So, when you are in the middle of the countryside with no network - no maps!
Wifi senisitivity was good, but not outstanding. It was better than Free's two wifi phones, but not as good as the Twin Tact or the wifi in my Acer Aspire One netbook. Not a problem when you are using it in a small flat, but vital if you are on a high floor in a hotel with the access point at ground level.
There is (at present on SFR's android portal) no Skype app, only Skype Lite, which involves calling a landline phone number, since voice part of the call is carried over the cell network. So, expect to pay massive roaming costs if you use it abroad.
Android, in its wisdom, does not allow users to change the proxy settings. Fortunately there are web forwarding sites. But they are limited.
A life-size test: see plane departure times while sitting in an airport lounge. Turned out to be almost impossible.
My review model came without a headset. Very awkward for use in public places, such as airport lounge.
It transpired not to be compatible with any of the other headsets and hands-free sets I had, including models with the same type of mini-USB plug and a high range Parrot bluetooth handsfree headset.