I think this thread proves one thing - Abraham Lincoln was right.
And, I just love it - I see a post where someone doesn't like Bluffside, and 3 posts later, someone mentions loving it. Funny.
Books I regret (now, this isn't any indication of their quality, mind you, I've just never really used them to the extent that they paid for themselves:
FRCS (WoTC) - yes, it's beautiful, yes, it's really well done, but I don't play in an FR campaign, and the mechanics are generally too powerful (spell prodigy, anyone? Order of the Bow Initiate, anyone?)
Alchemy and Herbalists (Bastion) - yes, it's a well done book, but I've just never used it. I think they could have done *more* with it. As it is, it seems like it is mostly just fluff.
Dungeoncraft (FFG) - It's a perfectly good book, but there's nothing in that I couldnt' have written myself.
Manual of the Planes (WoTC) - I like it, I've just never gotten any use out of it. Fortunately, I got it at Hastings (think Borders, but smaller) for 50% off, so I don't really regret buying it for $15.
Things I've gotten a lot of use:
Book of Templates (pdf/Silverthorne) - just an awesomely useful book, with lots of wicked cool templates. For the most part, these seem culled from other d20 sources, but it's a handy book if you don't have all the other sources. And, at $12, it's a steal.
Requiem for a God (pdf/Malhavoc) - I just love this book. And while I agree with the poster above that some of the stuff should be *more* powerful, it's easy enough to modify. The fluff is quite good, and it's a great idea book. I just wish the OGC were more forgiving (my big complaint about all of Monte's stuff)
Tome of Horrors (Sword and Sorcery) - just a great collection of monsters. Should be on every DM's shelf.
Others that see a lot of use: Bluffside, and Artificer's Handbook, but mostly because I wrote/co-wrote them.
