[Porcelain God]

Combat stats are of particular focus in the MM. I agree that they are not the most important aspect of creatures in the game, and it is for exactly that reason that I appreciate that all those stats are all in the MM so I didn't have to endure the tedium of trying to come up with them myself -- I much rather spend my imagination trying to get in the head of the creature. So the MM did the boring part for me and left me with the more interesting stuff to ponder -- seems like it has the right focus. Many of the "ecology of the" articles in Dragon fleshed out the bones very well if you needed further fuel for the imagination.

At the end of the day, if you are doing to run a 1e game, somebody in the group is going to have to have a PHB, DMG, MM, and the Dragon magazine archives. The latter is really indispensible as it offered many alternatives that fixed many of the problems in all three books (like the abyssmally weak dragons outlined in MM that could be dispatched with ease by low level parties) -- issue 50 alone presented two alternative formulations of dragons that gave them some real teeth, my personal favorite being "Self Defense for Dragons".