Watch the tach when you try to start the car. Does it move on the instances the car won't start? If not it would just be another sign pointing toward the dizzy, I had the same issue back in the fall, as well as the car routinly shutting off running down the interstate at 70+.
I bought a new distributor from Advance, which has solved both issues. It wasn't much more than the remanufactured piece, not sure how it will hold up over time, but it does have a lifetime warranty.