I think this is a very personal/comfortable choice. For me, I find that the lower down I go with the barbell, the more it works my front delts. So much so that it inhibits my bench workout. For this reason, if I'm doing a barbell bench, I'll go just a tiny bit past paralell with the elbows. I'd rather work the front delts individually than while I'm working chest. If I rely too much on the front delts to push the weight, the less my chest benefits.
For you guys, this mostly will depend on the size of your chest. If you're a beast, touching your chest may only be just past parallel.