What specific stuff from d20 products are you using?

[Arnwyn]

I use a fair amount of 3rd party stuff (well, in theory, anyways) in my fairly extensive FR/SJ/AQ/PS/KT campaign:

R&R 1-2: including spells, magic items, PrCs, and Ritual Magic.
BoEM 1-3: pretty much everything.
BoHM: pretty much everything except that absolutely ludicrous Hallowed Mage. Gack.
Airships: for Halruaa and Nimbral.
CC1, CC2, ToH, RL: DoD, Nightmares & Dreams, Jade Dragons & Hungry Ghosts for monsters.
All Necromancer Games and Malhavoc adventures, plus some from Monkey God and Kenzer.
All Rokugan books for my version of Kara-Tur.
Gladiator (by Mongoose) to cover the South's gladiator arenas.
Guilds & Adventurers (by MEG) to cover some of the merchant aspects of my campaign.
Dragon Mag and Dungeon Mag.
Everything Freeport.
Some SL city books: Mithril, Hallowfaust, Shelzar to cover some cities in the South.
Kalamar city book: Geanvenue (also to be put in the South).
Some other (less impressive) books I might have forgot.

Edit: stupid smiley removed...

 

[Estlor]

I'm working on a homebrew campaign setting that's a strong departure from standard D&D (but not quite to the extent of AU). I'm pillaging the d20 stuff I own for ideas. Things I know I'm using so far:

• AU: The unfettered class, some of the feats, parts of the totem warrior class for my shaman core class, and parts of the spell system for the shaman's supernatural abilities.
• S&SS: From Relics and Rituals 1 & 2 I'll be using the spells generate heat for the sorcerer, mystic, and channeller classes. I'll also be removing planar travel spells from their spell lists and replacing them with spells from these locations. Tattoo magic is going to be included. I'm going to consider each prestige class individually based on how well they fit the campaign setting's feel, but I'm sure one or two will make it.
• FFG: I'll be using steam technology and firearms out of Sorcery & Steam. I'm adapting the Soulmech from Dragonstar for use in the setting. Midnight's spellcasting system is going to be used as the base for bards and rangers as well as any other class that takes the feats that power it.
• IK: The gun mage class they released a few weeks back is being overhauled to work with guns or bladed weapons and being called the channeller core class.

That's all I can think of off the top of my head. But considering the setting only has the human and elf race from core and drops/replaces a number of the core classes, there's probably something I'm forgetting.

 

[woodelf]

Dynasties & Demagogues: woohoo! social-interaction rules!

Anyway, it's one of the few D20 products out there to bring something completely new to D&D--most of the rest are just more of the same (new feats, new magics, new classes, new monsters, etc.). Not that they aren't better than the stuff in the core rules, just that i have more need for something all-new (the stuff in Dynasties) than for improvements over existing stuff (which is passable).

Oh, but in the "more of the same" category: the Net Book of Feats. Best collection (professional or otherwise) i've seen yet. I particularly like the ratings system, so you know right up front which feats are imbalanced, in what ways, and by how much.