Best RPG purchase past 6 months

[Silver Surfer]

Magical Medieval Society: Western Europe. It's really awesome. IMC, all of a sudden the PCs wanted to estimate the number of smiths in a town, and I could tell them...
In general, the thoughts about the effects of spellcasting on a medieval society in general are quite insightful. I've always wondered what impact the possibility of, for example, Raise Dead had on everyday life.

Second best purchase would be MotP.

 

[WizarDru]

Hands-down, Magical Medieval Society: Western Europe. I haven't gotten BotR yet, but I've heard very good things about that. Runner up would probably Savage Species, a book I expected to be poor, but actually rocked.

 

[NiTessine]

Fiend Folio. So much cool stuff to make the PCs lives difficult with...

 

[Gnarlo]

Does my in-home ice and Mountain Dew soda dispenser count as an RPG purchase...?

Mommy, can I go play at Mark's house?

 

[Malin Genie]

Universalis without a doubt.

 

[Joshua Randall]

1st place: Tomb of Horrors (use it all the time, every week)

Every week?! Yeesh, the death toll in your campaign must be really high!

Or did you mean the Tome of Horrors?

 

[TrubbulTheTroll]

Without a doubt, Races of Faerun... satisfied my hunger for good Realms stuff and answered a lot of questions I had about the Realms peoples.

 

[Synicism]

Probably Nobilis and Savage Worlds.

 

[proditor]

1st: Anything by Hero Games.
2nd: H.P. Lovecraft's Dunwich

 

[Gospog]

For just D&D, the Monsternomicon.

For anything D20, the Star Wars Hero's Guide. Just plain awesome!