The Max modifiers are named after what they do, so even for Blender users it'll give an idea of what function to use (assuming Blender has the equivalent).
You haven't used Blender have you? It has a lot less modifiers than max, though then again, it has had sculpting for a while unlike max, and most of the modifiers missing were pretty pointless anyway.
You should try it out, it has some nice features. The same names have different meanings in the two programs, and modifiers that do the same thing have different names too.
I haven't seen a noise modifier similar to max's in Blender myself, just a noise tool which seems to do something different, but I've seen displacement maps used, Zackg could use that.
I don't know about the whole chopping a piece off part. If you leave it as a complete sphere-ish rock, you have a lot more freedom in placing it. The original rocks, you couldn't flip them upside-down, so they were all more or less the same way. If you leave the bottom on, you can flip them any which way, which can provide more variety.
For simple spherical rocks, you can use your method (though tbh I think zackg doesn't want something like that), my method is for making craggier rocks.
It takes two seconds to make a bottom to it if you really want one though, just select the bottom edges, bridge, and extrude. Alternatively use symmetry then FFD and optimize.
Anyway, he's using Blender, so if he wants to edit a sphere, he might as well sculpt it.
I suggest just sculpting the rocks anyway, no need to get overly compicated, sculpting is easy and looks great.