Most likely the starter contacts. They are easy to get to and replace. See the following links.
http://www.automotiveforums.com/vbul...d.php?t=166530
http://www.4crawler.com/4x4/CheapTri...OnlineOrdering
http://www.off-road.com/toyota/tech/starter/
I would put battery connectors as less likely to be the problem than the starter contacts. Still a possibility though.