Not including Campaign settings. What do you think is the best supplement WotC has done so far for 3.5?
My first and most emphatic vote is for Lords of Madness. The perfect blend of fluff and cool rules. Combined with the far realm stuff from Dragon, creates a totally new campaign flavor.
Also: Expanded Psionics(massive improvement on 3.0) and Complete Adventurer (so many good options!)
I'm a fan of so many, but the latest I'm reading, Heroes of Horror, is really impressing me. Quite creepy.
Lords of Madness was a delight as well.
That Heroes of Battle (title?) book was the only one that had me, upon finishing, wondering if it was missing some pages. A lil content light.
I want all upcoming texts fed a steady diet of protein shakes slathered in a corn syrupy froth cuz I want them all fat as Santa.
I liked the Lords of Madness as well, but the four Complete books left a little to be desired. They were usable but nothing sensational.
The Complete Adventurer was worth it for the Scout and Ninja classes alone, as was the Complete Warrior for the Swashbuckler and Hexblade.
In the Races of books my personal favorite was the Races of Stone. Probable the best crunch book (especially if you love dwarves) and the only good new race (the Goliath) of the three main Complete books.
My personal favorite would be the Expanded Psioincs Handbook. Its all crunch but it is a real good treatment of psionics for 3.5 and adds an additional layer to any D&D campaign that chooses to include them.