I usually go for for 12-15 reps with a weight where the last 3-4 reps are extremely hard but still doable if I'm training endurance.
You can do the 20 rep breathing squat routine, but it is extremely hard.
http://www.bodybuilding.com/fun/irontamer5.htm
I usually say 1-4 reps build strength, 5-8 build power, 8-12 build endurance. You can of course go higher than 12 for endurance.
Weights should be adjusted accordingly. So if you can squat 225# for 8 reps, you should figure out how you can squat for 3 reps, and build from there.
A real world physique is a function of your diet. Any lifting program that involves serious squat training will yield impressive results if you eat right.