I just found out about D100/BRP/Chaosium family of games and how they are my favorite thing ever, and i have an excuse to buy more books. But since i am not made of money and i also like to have at least some reason for getting a book (best version of the rules, great art, interesting mechanics etc.) i need help deciding what to pick up, especially out of print books, some of them are really expensive. All of my opinions and decisions what to buy are based on forum posts, i read only Mythras Imperative and skimmed PDFs of a couple of Stormbringer editions.
Runequest
I want to get RQG, Mythras and 1993 Avalon Hill Deluxe Edition.
As far as i can tell RQG has heavy roots in RQ2 with some improvements and gorgeous art, and Mythras is descendant and refined version of Mongoose Runequest so there is no reason to hunt down other versions. 1993 edition of RQ3 has full rules in a single book and can be found for decent price. Any interesting supplements for Avalon Hill RQ3 that i should hunt down (most interested in mechanics and art), am i wrong to "ignore" other editions/versions of the game? Any of Mongoose Runequest (now Legend) supplements i should look at?
Call of Cthulhu
Ordered 7th edition slipcase set (it is gorgeous), and as far as i understand it is somewhat significant change from older versions that were mostly small incremental changes. What older versions should i look at, should i just get 40th anniversary/20th anniversary, should i even look at older versions? Any older supplements/adventures that are worth hunting down? Anything really cool in those old boxed sets?
Stormbringer
Searching for Elric of Melnibone RPG introduced me to D100 games, i already ordered copy of Elric of Melnibone by Mongoose for their RQ2, i saw it was out of print and fount new book for great price.
Other versions are really confusing, seems Stormbringer 1-3 are mostly the same game (and 3rd edition published by GW is significantly more expensive than 1st edition), with 4th edition changing magic for the worse while doing everything else a little bit better. Elric! and Stormbginger 5e are made by same author and it seems that Elric! is better choice with a little less content but much better book and organization. I will get Elric! since it can be found for decent price, but i really dont know about older versions.
Pendragon
Dont know anything about the system and not really interested in the setting, any versions with interesting (and significantly different) mechanics than Chaosiums other offerings? What editions are considered the best? I presume there is a focus on mounted combat and relations with church/nobles etc, what editions did those the best?
Basic Roleplaying
Ordered the new edition, any point in getting the older stuff?
Other stuff
Any reccomendations, mostly interested in art and mechanics, especially if they tie in to the setting in interesting ways or represent/simulate them really well.