If you're concerned about winter traction I wouldn't go with the wider tire. I would stick with 235/75/15, or 30x9.5. I have 235s and they look pretty good, but I have a roughly 1.5 - 2 inch lift so I'm thinking 30x9.5s when I've got some cash to burn.
I've heard some sketchy things about general tires. Check out the Cooper AT/Rs or the Yokohama AT/S...the yoko's you can get from summit pretty cheap. I'm liking them for when my tires are shot.
Here's my jeep at stock height with the 235/75/15s. I've still got good pickup and I get a pretty consistent 20 mpg when I run Startron in the gas. The defender in the back is running 31's I believe. Not an excellent reference but they'll fit on a stock jeep.