Most people run between 2 and 3 degrees of rear toe. Generally, you're better off with 1 or 2 degrees of toe at the outer hinge pins (using 1 or 2 degree hubs) since that will prevent binding at the inner hinge pins. If you can afford it, get a set of both 1 and 2 degree hubs to use as a tuning aid.
Adding toe in at the rear helps "lock" the rear in.
Check the Xray setup book for more info.