Just about any modern xDSL router is going to have a host of features that you will likely not need. they can be turned off so it is of little matter. They will also work a bit better then the one you have in service right now thanks to better noise margins in the drivers and mod/demod circuits, software improvements, and faster embedded processors.
The short of it is just about any of them are good, I do like the Zoom xDSL routers, seem to perform well under adverse line conditions.
I would also look into putting the whole network behind a Smoothwall firewall. Go to
http://www.smoothwall.org for the skinny if you are interested.
Mike