Must have book per edition

[Shemeska]

1e: Manual of the Planes
2e: Planescape box set
3e: FRCS, Fiendish Codex I
4e: skipped it
PF: Inner Sea World Guide, APG

 

[pemerton]

I get the impression some of the stuff in W&M never made it into 4e.

Some of the substance changed a bit - eg angels end up being a little different in their core game backstory compared to W&M.

More significantly, the style and approach of W&M didn't make it into 4e, except in two places that I can think of: the discussion of the core conceits (though W&M does this in more detail than either the DMG or the Rules Compendium), and the discussion in the DMG of why 10 languages - which explains it not just from the ingame point of view, but from the metagame point of view.

Here is a feature of the 4e DMG that, for me, emphasises the absence of the W&M approach - there are many (very good) pages telling me how to build an encounter to achieve tactical metagame goals, but nothing at all telling me how to build an encounter to achieve story/thematic metagame goals. Instead I get half-a-dozen crappy pages on how to add colour to my adventure location - all of which will be completely meaningless unless I know how to make it come out in my encounters!

(While I quite like the 4e DMG and DMG2, for the sorts of reasons I've just given I'm not as big a fan of them as some people are.)

 

[Dice4Hire]

With the premise I am choosing books I could use for any other fantasy system, I choose

1E DMG, for sure. Just the tables alone are great
2E I will take the MM here, though it is mainly because I did not choose a
monster book elsewhere
3E/3.5E PHB It really is a gem and very close to a self-contained game.
4E Neverwinter. This is so close to systemless it is not even funny. And a great
primer for a DM on how to set up an adventure locale.
5E Dunno, but I'd love a good adventure to put here.

 

[MortalPlague]

I'm not seeing enough love for 4th Edition's Monster Vault. That book is the model I hope all other monster books follow.

 

[Storminator]

My favorite 4e book is The Plane Above. Actually interesting and readable.

PS

 

[LeStew]

Not a lot of Love for 4E here. Well here's my 2cents.

1E. never played
2E. Never purchased books
3E. Maybe Eberron. Love that setting.
4E. I think there's two camps to choose for. Players and GMs. For Players I'd say, The Player's Strategy guide. It really helps one define any character much less an RPG character. for DM's I'd say the DMG2, for helping to create adventures for the previously mentioned characters. much love for the Dungeon Delve book as well.

 

[Halivar]

I can't saying anything about OD&D, because RC is the only book I have for it. One day I'll run a strictly OD&D campaign, but I have yet to so far.

1E - The DMG is like magic for me. It's just a fun, readable book.
3E - Definitely Unearthed Arcana. There's a lot of freedom in that book to break out of the rigidly-defined core class structures. Our group switched to using gestalt in every campaign.
4E - DMG2. There is just a lot of good advice in there.

 

[Joshua Randall]

1e. Hmm. Frankly, as much as the DMG has that nostalgia factor, it's a terrible mess of fiddly random rules (which some people like, but I do not). So I'm gonna abstain here.

2e. Monstrous Compendium was indeed pretty rad, and a welcome relief after those horrible three-ring-binder thingies.

3e. Manual of the Planes, hands down. This book is brimming with evocative planar locales, adventure seeds, and yes even some random tables. Every time I read this book it inspires me.
Honorable mention: Player's Handbook 2, for daring to change some of the core rules (around, e.g., druid's shapeshift) to make certain classes play better.

4e. Has the best DMG (and DMG2) of any edition to date, but I'm going to go with Monster Vault. As good as 2e's MC was, 4e's MV is better.

 

[Steely_Dan]

My personal all-time favorite is 1st ed. Legends & Lore.

A book with Asgardians AND Arthurian heroes? Count me in!

My all time favourite book is teh 1st Ed Deities & Demigods, love the Jeff Dee art, and that Melnibonean chapter is what really sucked me into D&D.

-Basic Rulebook (Moldvay), is what I think is the ultimate core/essential D&D book.

-1st Ed: MM

-2nd Ed: PHB (but I think the 1st Ed ranger is better)

-3rd Ed: PHB

-4th Ed: PHB

 

[Nellisir]

2e. Monstrous Compendium was indeed pretty rad, and a welcome relief after those horrible three-ring-binder thingies.

[nitpick]The Monstrous Compendium was "those horrible three-ring-binder thingies". Monstrous Manual was the hardback compendium that replaced the MC.[/nitpick]