I upgraded from a Nokia N73 to the XDA Orbit 2 in March and it has to be the best phone I have ever had.
I still rate my N73 as it was a great phone but the Orbit 2 has opened new worlds to me.
The OS is Windows Mobile 6 Professional which some purests may oppose but is still brill, going from S60 to this was a revelation.
It has 3G, EDGE, HSDPA and WIFI connectivity to the internet and gives me full access to my msn Live emails.
Full Sat Nav for UK & Ireland as standard. It has a touch screen and comes with x2 stylus and the Touch Flo cube (rotational 3d cube for launching apps, music, video, photos all by swiping your fingers across the screen).
I've been thoroughly impressed by this handset. The HTC range gives such a variety of comms units all with a bit of class.
If you are due to upgrade soon I would suggest looking into either this phone or something similar. If you are serious about being in constant reach of your emails, internet access etc this is definitely for you providing you go for an unlimited data plan which O2 offered as a courtesy "Bolt On" extra when taking out the contract @ 40 quid a month (worth every penny IMO)
The only thing I've found, and my reason for this post is that no one else seems to have one or even know about the XDA Orbit 2.
Do you own one?
What do you think?
I could go on...

but I won't!