I found this in a guide somewhere...
can anyone confirm if this works?If you use the target nearest enemy key often and find it not selecting targets because they are too far away,
go to the World of Warcraft/WTF/ directory and edit the config file.
Append the following line:
SET TargetNearestDistance "40.000000"
You can also enter other ranges depending on how far away you want to be able to target mobs.
Now I just have to sleep (it's 03:35)