hey doug welcome!

ive been in the hobby for about 7 months and i still consider myself a newbie as well but you're right, the info these guys give is phenomenol(sp?).

base rock, to answer some of your questions, is normally cured(meaning it has gone through its cycles of ammonia spikes and whatnot) but it does not look a pretty(lack of a better word). it is called base rock because normally it is the rock used to fill up the space between the good looking rock on top and the glass and sand. its more like a filler so you dont have to spend so much money on really pretty pieces of rock(since most places like tims can get you good deals on base rock)

the show rock is fully cured but usually comes from dead coral reefs so is mainly comprised of some really beautiful skeletons on which you can cement your coral fragments(frags). this is the type of rock work that you really want to focus on when making your tank purdy. this is usually shipped in from different places like fiji and the tonganese islands that is where you get the names for the different types of rock.

i have heard from other places that limestone will eventually deteriarate(sp?) putting alot of calcium and alkalinity into the water(for freshwater this is bad for business but can be very beneficial to saltwater if controlled properly).

besides that, there's not much more i know about live rock, hope this helps ya!

regards, steve