I have always heard that the legs (quads and hams) can effectively grow in the 20+ range and that one should always train calves in the high rep range. Truth to these?
Not that I've noticed. I can't stand higher rep ranges, I feel like a dork that's not even working out. I know its absolutely ridiculous from a scientific perspective but I just really enjoy the 6-8 range; I sweat like a pig, and throw up moderately heavy weights for all the sets I desire. I'm not even on a traditional 'routine'; I incorporate a base compound lift into every split day, but other than that I kind of just do what I want and make sure that all regions of the target muscle group that day are taxed by exercise. And I am growin' indeed.
I really think it's best to have higher reps in there though; I think I'm going to alter my 'routine' so that after I'm done with my fun 6-8 rep exercises I'll do some 15-20 sets and eek out that last little bit of available strength in the muscle. I've had good luck with that before, gets me sore which doesn't happen unless I'm doing something different than usual, but I have trouble sticking to it. The PHAT program is pretty good about this, and with some modifications it works well while on gear; volume needs to be increased but you can throw in exercises of your choice to do that.
I should probably get my ass a regimen and stop playing around just doing what I want, but it actually ends up being a routine because what I want stays the same for a fair amount of time. After a month or so I want to do some different forms of the exercises so I switch it up. It's oddball as hell but it's working well.