Psion
Adventurer
It's really not worth doing a 100% breakdown of my shelves, but here goes:
WotC: 95% of D&D stuff. I decided to no longer support FR or SW. D20 Modern I'll do on a case by case basis.
AEG: All one-word and spycraft stuff. I am getting L5R swag, but really think you don't need any of the new clan books. Not following Swashbuckling Adventures.
Green Ronin: Got it all. Pure gold, bay-bee!
Malhavoc: Got it all in PDF form.
FDP - Got it all. Like the counter collection but to be honest probably won't buy more counter packs. The first one was right up my alley, but 2&3 was a little redundant.
S&SS: Most of scarred lands and a few Ravenloft titles. Not collecting Ravenloft, pretty much only committing to the big hardbounds for Scarred Lands.
Kalamar: Have most of the non-adventure material. Don't care that much for the adventures.
Mongoose: About 60%. I have most of the Quint material and Encyc. Arcanes, but after a few bad titles will only be picking up new ones on a case-by-case basis. Avoiding Slayers Guide except Dragons, Undead, and Yuan-Ti. Not following Slaine, Judge Dredd, Armageddon, etc., but will be getting B5.
Necromancer - Tome of Horrors, Necropolis, and many adventures - the RA series, Demons & Devils, Rainbow MAge, ToA. Slowed down on buying buying adventures as I do not use them as much.
Natural 20/Ambient/ENPublishing: Have most of their stuff prior to about 6 monsth ago. Never got a copy of three arrows, elements of magic, or anything that came after.
Mystic Eye - The campaign setting and most of their newer stuff.
Perpetrated - Both of em.
FFG - Most FFG d20 products. I eventually decided that their mini-adventures weren't worth it and swore off of them. I have most of their hardbounds.
Bastion: All of it. Much of it is swag, some of which I wouldn't have bought on my own (Guildcraft), but the recent stuff is pretty decent. Spells & Magic and Arms & Armor are actually proving pretty useful.
Atlas: A few titles here and there. I only have swag adventures. I have Occult Lore (a way under-talked-about book!), Seven Cities, Seven Strongholds, En Route, Touched by the Gods. Want Nyambe, but as I am trying to limit myself to stuff I will actually use and I don't see running a game of it, it slipped off of my "must buy" list.
Monkey God - A few adventures, some of them cool (Song of Storms, All the Kings Men.)
OWC: A few swag items. I am honestly very disappointed with them and have yet to see a product I would buy on my own.
FFE: A strong smattering. Most of the items of power series, a few of their map books, orcquest, dungeon world. Most of them swag, some of which I would not have bought on my own, but I do like their map book products (Treasure Quests / Enchanted Locations.)
WotC: 95% of D&D stuff. I decided to no longer support FR or SW. D20 Modern I'll do on a case by case basis.
AEG: All one-word and spycraft stuff. I am getting L5R swag, but really think you don't need any of the new clan books. Not following Swashbuckling Adventures.
Green Ronin: Got it all. Pure gold, bay-bee!
Malhavoc: Got it all in PDF form.
FDP - Got it all. Like the counter collection but to be honest probably won't buy more counter packs. The first one was right up my alley, but 2&3 was a little redundant.
S&SS: Most of scarred lands and a few Ravenloft titles. Not collecting Ravenloft, pretty much only committing to the big hardbounds for Scarred Lands.
Kalamar: Have most of the non-adventure material. Don't care that much for the adventures.
Mongoose: About 60%. I have most of the Quint material and Encyc. Arcanes, but after a few bad titles will only be picking up new ones on a case-by-case basis. Avoiding Slayers Guide except Dragons, Undead, and Yuan-Ti. Not following Slaine, Judge Dredd, Armageddon, etc., but will be getting B5.
Necromancer - Tome of Horrors, Necropolis, and many adventures - the RA series, Demons & Devils, Rainbow MAge, ToA. Slowed down on buying buying adventures as I do not use them as much.
Natural 20/Ambient/ENPublishing: Have most of their stuff prior to about 6 monsth ago. Never got a copy of three arrows, elements of magic, or anything that came after.
Mystic Eye - The campaign setting and most of their newer stuff.
Perpetrated - Both of em.

FFG - Most FFG d20 products. I eventually decided that their mini-adventures weren't worth it and swore off of them. I have most of their hardbounds.
Bastion: All of it. Much of it is swag, some of which I wouldn't have bought on my own (Guildcraft), but the recent stuff is pretty decent. Spells & Magic and Arms & Armor are actually proving pretty useful.
Atlas: A few titles here and there. I only have swag adventures. I have Occult Lore (a way under-talked-about book!), Seven Cities, Seven Strongholds, En Route, Touched by the Gods. Want Nyambe, but as I am trying to limit myself to stuff I will actually use and I don't see running a game of it, it slipped off of my "must buy" list.
Monkey God - A few adventures, some of them cool (Song of Storms, All the Kings Men.)
OWC: A few swag items. I am honestly very disappointed with them and have yet to see a product I would buy on my own.
FFE: A strong smattering. Most of the items of power series, a few of their map books, orcquest, dungeon world. Most of them swag, some of which I would not have bought on my own, but I do like their map book products (Treasure Quests / Enchanted Locations.)