[I have read what Sheldon has to say and am still a little confused.]
I have an old style American bottom bracket (frame's from 1981). One piece cranks. Am I doomed in my hope of getting nicer cranks/chainring? I also would really like foot retention but the pedals are like half-inch or something and nothing fits. If I could get new cranks obviously this would solve that problem, but do they make modern crank-sets that would fit my giant bottom bracket?