1987 Chevy Celebrity starting problems

I inherited a 1987 celebrity wagon. i started by replacing the dead battery and replacing all the brakes including drums, rotors, pads, and even the brake lines. during these repairs the car started and ran fine. recently i have had an intermitent problem with the car stating, that has turned into every time now. the alternator is charging the battery just fine, but now i cant get the car to start without a small jump. when i get a jump every thing starts quickly and the starter works fine. I feel that between the battery and the starter something is not working correctly, either the ignition switch or some kind of electronic controll that works with a jolt of electricty.
Any ideas where i should start?