If you can only afford one 3.5 book...

[AnthonyRoberson]

I would make it the DMG. The epic and planes stuff, the better organization, trap creation info, encounter tables, spell templates...this is a much better book than the old one. Kudos to the designers at WOTC.

 

[dren]

Since I don't use standard magic items, create personalized encounter tables, use my own epic / high level stuff...the only book I really need is the MM.

 

[Desdichado]

MM is the only one I see as a "must have." PHB next, DMG is last on the list to pick up.

 

[Morik]

My list would be:

MM (this one I would like to have)
DMG
PHB

 

[Ravellion]

PHB for the spells and combat chapter. The rest you can do yourself (Templated NPCs for foes & custom magic items). Spells are just too annoying to make up.

Rav

 

[Plane Sailing]

I would suggest DMG as the best single book to have.

Not because of the magic items, which are a relatively small part of it, but because of the excellent help for wilderness adventures (never before seen) and planar adventures (best bits from Manual of the Planes).

As Antony said the trap stuff is all new too.

The MM is handy, but you could run all the existing monsters quite happily.

The PHB is important for new classes - but the guts of that will certainly be in the SRD.

So my suggestion for most DMs would be the new DMG.

 

[Desdichado]

Yeah, but I've already got hundreds more than I can imagine ever using too. (edit: referring to spells -- another post snuck in there making mine unclear to whom I was replying.)

 

[Plane Sailing]

snuck, snuck

 

[Drawmack]

Since the bulk of the MM and the PHB will be in the SRD but much of the DMG will not be I would say if you can only afford one book go with teh DMG and use teh SRD for the other two. Then when you have the money pick up the other two in this order MM, PHB.

 

[Desdichado]

snuck, snuck