new nextel phone, do I need bluetooth?

want to get some opinions on this...
I MUST get a new nextel phone, i currently have the i60c with a wired
earpiece. I need a new, more up-to-date phone, and I definitely want to be
able to to have a WIRELESS earpiece. From what I can tell the only way to
do this is to have a Bluetooth-enabled phone, and there are only 3 Nextel
phones that are that: i870, i605, and the blackberry 7520. I have a Garmin
iQueM5 with bluetooth that I live and die by, I now need a phone that will
work hand in hand with it...

so what I DEFINITELY need is this:

-a wireless earpiece to work with a nextel service (so it must be
bluetooth?)
-small phone, prefer a flip phone model, somewhat durable is good (i'm in
the contruction/rehab biz)

what I DON'T need is:
-email capability
-MP3 player
-camera (although it would be useful if it can take good enough pictures to
use on the web and store a decent amount of them!)

questions:
-does anyone currently use the i870, i605, or blackberry 7520? reviews?
-does anyone use the bluetooth adaptor? thoughts on that considering I'm
already getting a new phone that I want to be wireless?
-if I am using a bluetooth adaptor, whats the suggestred phone to get for my
needs?
-when will nextel be coming out with MORE phones that work with the wireless
headsets?

thanks,