Depends on how and where the 2wd truck is to be used.
I keep AT's on my 2wd Dodge/Cummins with the anti-spin crappy diff...however when when heavy snow falls or I have a need to get the truck in my or someones muddy pasture (moving cattle) I keep a pair of mud terrains for that purpose.
I also have 6+ miles of county roads to get to a state hiway. The county sometimes are several days before plowing the roads open after a major snow storm.
I wouldn't put a mud tire on the front of my 2wd trucks as a good all terrain will get better traction overall.
Now on my 3500 DRW chevy crew cab 4x4 454 gazz guzzler and the wifes 1500 4x4 I keep a fairly aggressive all terrain on them.