Hans,

I have a Sprint HTC Hero and down here the 3G is something to be desired, but since almost everywhere I go has wifi, the lack of 3G has not been an issue. Last I was up in the phoenix area the phone absolutely rocked! The speed in everyday things was much faster, the 3G network loads websites faster than my 8MB cox connection at home. I was seriously impressed with my phone all over again.


Your requirements:


Required features:
. bluetooth tethering
. ability to turn off GPS if one is available
. ssh out
. bluetooth
. connect to my own mail servers
. root access
. play ogg-vorbis
. contact, etc. syncing w/ GNU/Linux


All of this is trivial if you have rooted your phone. I'm still waiting for the Android 2.1 update to hit my phone officially, which should happen in the next few weeks. If not by the end of April I will root my phone, but with everything else going on right now I am trying to be patient with my phone and try the real rom first. Sprint supports tethering out of the box and I can surf and talk at the same time. I use the wifi tethering quite a bit when I use some laptops that do not have OSS drivers for their wifi in linux, I plug my phone in and go. 

I use KDE for everything, very little Gnome stuff. The latest KDE 4.4.0+ has an akonadi-google plugin so now my kontact (kmail, kaddressbook, korganizer - calendar) all sync with Google which means my phone.



 
Desired features:
. tether and call at the same time
YES 
. on phone internet connection and call at the same time
YES 
. ssh in across cell network
Must root phone for ssh, I have not needed it yet. 
. USB tethering
YES 
. fully functional while charging
YES 
. root access w/o jailbreaking
NO 
. wifi
YES 
. tetherable via wifi
It did not occur to me to even try this... 
. phone to phone communication via bluetooth
YES 
. phone to phone communication via wifi
Not tried. 
. GPS
AWESOME! 
. camera and video
5MP is great and my kids look great in the videos. 
. external storage card, prefer sdmc
Micro-SDHC and I use a 8GB card which so far is plenty. MUST BE AT LEAST Class 4. Seriously spend the money on a GOOD Class 6 because it makes a difference in general usage with the phone. 
. can use external display ( monitor and/or TV )
HTC has a special USB cord that allows this. It uses a standard mini-usb (micro? not sure) same on most external usb hard drives, but it looks proprietary. The cord HTC uses has a different shaped end to allow video and audio output. Regardless, a standard usb will plug in. I just about paniced when I opened the box and saw it was NOT a standard cord. A little google searching showing someone saying 'Dude, just plug a regular usb in it!' so I did and it works fine.