Default Where to ... and what version ?

Well, after wandering on the web looking for a PDAphone I am very close to acquire a HTC Magic.

Only doubt: the fact that the Hero will soon be available (but at which price?).

The $$$ will probably do the difference, so ... a little question. There are several opportunities on the net but I have seen that there is not A Magic but THREE Magics:

* one for Vodafone taking datas on 900/2100 MHz
* one called ION on 1700mhz/2100mhz
* and one for Rodgers on 850 and 1900MHZ and this a bonus of 96Mo of RAM.

QUESTION: Which one will be good for me on an Orange french network?
I don't understand the differences between data networks and specs, sorry