I have a 69 el camino and I am in the planning stages as well. I currently have Monte Carlo discs on mine and it stops all right with the factory booster. You can run a B-Body spindle from what I understand to increase the camber gain and make it handle better. The issue is there isn't much in the way of B-Body brake kits out there.
I am probably going to go with this package for my suspension as it provides everything to make the car handle right and is a pretty reasonable price. Plus, it will work with the stock spindles. I've seen most of the manufacturers parts up close and the finish and quality on the Speed-Tech stuff is really good.
http://www.speedtech-performance.com...rod/prd186.htm
Wilwood makes a couple different brake kits that will fit the stock spindles too. Their prices are reasonable and you don't have to buy a big huge booster to get good pedal feel.