For most repairs that will need extensive tools, you will most likely need a tow to a mechanic, so just carry a basic set of Screwdrivers, sockets, wrenches, etc. Basically what you would need to, say, put a radiator hose back in place. DO carry though Duck (duct) Tape, some extra oil, transmission fluid, redi-mixed coolant, and things like that. Oh, and the most important: A good jack, and a lugwrench that fits ALL of your lugnuts (they sell a tellescoping multi-size lugwrench at Schucks/Kragen/Checker Auto Parts (i use it and like it alot, extra leverege and it has all the sizes for my lug nuts, which have different sizes for some reason.)
But in a nut shell, you really will have no use for a whole lot of tools on the side of the road( but a tow rope helps too!) Thats all that I have ever carried in my car, and it suits me just fine.
Brad M.
<i>(The AAA guy)</i>