I'd put it in the rear.  Driving with a welded rear end is no big deal, and after a few times driving it, you'll never even notice.  You'll chirp the tires a little bit, just go easy on the throttle around corners.  You'll get a little more wear out of the tires, but not a significant amount less. 

On the flip side, if you put it in the front, it'll be unused and not affect daily driving at all until you put it in 4wd.  The issue there is the greater possibility of breaking front end components.  Steering is usually affected offroad, it becomes harder to manuever the front end. 

So really its up to you, either one is a good possibility, and many people have either or both in theirs.