I think the basic idea of sticking with a set of "jack off all trades" type pliers is best, simply because you never really know what you are going to be up against.Of course, there is the idea that the visegrips can be left "loose" and used just like pliers too, but I like the idea of keeping it simple.
If you aren't familiar with the Autotool...
I just bid on one at ebay. It's a little pricey for my blood though.
I could see a channel-lock type plier/wrench in a multitool as the standard plier as well as a thickened flat area to use for hammering.
Another item for my Perfect Tool - Half Round file instead of flat file.