ExRayTed, don't forget that having longer levers (arms/legs) doesn't automatically help when lifting big, in fact they can be a distinct hinderance in some regards. The people I know who lift the most, effortlessly, seem to be quite short and stocky, because they are going through a smaller range of motion and lifting for shorter distances it is easier for them in some ways.
Genetics as mentioned is likely to be the main determining factor, I do agree that lifting big probably shouldn't be the main aim though, I'd prefer to lift 2/3 of the weight with perfect form than go all out and ruin myself with sloppy technique.