Skippywheels,
I went with 235/55ZR-17 tires on 17x7 wheels on my '84 wagon. That combination has the advantage of being a near-exact match to the stock wheel/tire diameter, so gearing and speedometer stay the same, but the contact patch is much larger for road handling. And the extra flotation doesn't hurt off-road, either.
Here's a picture:
and a link to my original post on the change:
http://forums.amceaglesden.com/index.php?topic=42205.0. The original post has more pictures and a description of a few body mods I had to do.
I don't know if the pictures will come through... sometimes the 'Photobucket' images seem to show up and sometimes they don't. If there's a way to upload images directly, I don't know it.
JB