Oh Let's see:
I regret the following purchases:
Dieties & Demigods - complete waste of money - I pre-ordered from Amazon, expecting a remake of the old Dieties & Demigods and instead I got the author's personal campaign pantheon with some norse and greek deities thrown in as a second thought.
Star Wars OCR - got it - never got a chance to play - and then found they re-did the book a few months later...
Rokugan - Played in 3 sessions of a Rokugan campaign.
Stuff I'm glad I didn't purchase:
Savage Species
Quintessential Anything
Any FFE product
Epic Level Handbook
Stuff that was hit-and-miss:
The splatbooks - only in light of the 3.5 release the release of Complete Fighter, as well as the upcoming release of Complete Divine. I'm fully expecting them to also release Complete Arcane, Complete Performer and Complete Stealth. The thing that makes me angry about this is the fact that some of the PrCs that got converted shouldn't have and vice versa. I mean - come on - the Deepwood Sniper from S&F? Sure it is probably unbalanced - but the concept of this PrC is more important. Instead, they do a conversion on the Knight Protector of the Great Kingdom... (Haven't we got enough - with the Purple Dragon Knight, Knight-Errant of Silverymoon, Knight of the Chalice, Knight of the Middle Circle, Thayan Knight?!?!)
Stuff I'm really glad I purchased: Races of Faerun - had everything that FRCS should have included. Any FR book, especially Silverymoon. We need more informatio on coinages, foods, commerce, etc. and less PrCs.