One thing to remember at 48" you are only cutting one sheet of drywall but it makes it a little harder to tape and mud the seam due to the fact that the area at the top of the box is a bevel on the next sheet of drywall. 52" seems to be a better height for that and for leaning a 4x sheet against the wall. I don't know how many times I have had a piece of plywood or drywall against the wall and that outlet would have been handy to have access to. Also if any weight against the outlet, you can bust the cover. Not a big deal but something to consider.
If you plan on having plug in clocks, tv, stereo, or whatever higher up. add some outlets there also. I have one in each corner of the ceiling just in case I want to plug something in that I will have in the corner. Also add an outlet close to each corner in case you have a plug in gas pump or some similar item you want to put there.
If you have to run the wire anyways, it's just as easy to cut in an outlet along the way.