Yeah I got Pavis & Big Rubble when it came out from MD. I neglected to mention those (as well as Griffin Mountain, yeesh, what an oversight!) I think my softcover of P&BR was around $40 ?, IIRC. I still prefer that old boxed format though..must be the "old school gamer" in me

(and the boxed sets were more useful at the table, as the "common knowledge" books for the players were easily given to them, you had the separate maps, etc etc.)
In addition to all the cool stuff mentioned here about Glorantha, probably the thing I love best is that everything may be the truth, or may be a lie- it all depends on your cult's POV and there are contradictions everywhere. Just makes thing much more interesting, and certainly opens up alot of interesting RP opportunities (though it can get REALLY confusing at times)