Ok, what are some of your favorite game support products?

Personally I think that gurps vehicles, revised, is one of the best, most useful game products ever done for any system. I like SF games and it was a SFRPGers dream. When you got done with a vehicle in gurps vehicles, and yes it took a while, you knew damn near everything you needed to run a good SFRPG with it, the details were there.

Need to replace the powerplant with one salvaged from an alien ship? You know how much the plant weighed, what fuel it took, how long it ran, how much power it pot out, etc. Need to lighten the load to lift off while carrying fleeing refugees? You knew what your weapons and ordance weighed and how much weight you could carry after dumping them.

It was a pain to make a major vehicle in full resolution, I do admit, but by god whan you were done you had all the details you'd ever need for damn near any situation.

I liked it, still do. I'd recommend it to a SF writer as a tool for making vehicles and such and keeping them consistent.

Gurps Vehicles?

MT Vehicle Construction!
FF&S!

Those are way better.

Yeah Fire, Fusion & Steel has to be the best construction book IMHO.

I think the GMs Companion for Millenium's End is probably the best support book for a modern GM.

Rules of Engagement was a blast for Star Wars D6.

Covenants for Ars Magica (the original one, not the new one). A lot of info you'd need to know to create the home base of a group of wizards. The example covenants are colorful and very useful.

• Fire, Fusion & Steel (the TNE version) - Technical Architecture, 'nuff said :pundit:
  
• DGP's World Builder Handbook and its descendants TNE's World Tamer's Handbook & GT: First In - for world gen, first contact, and colonization
  
• GURPS: Uplift - for alien gen (GURPS Space 4e may be better but I don't have it)
  
• GURPS Low-Tech & Mysteries – what the title says & a great work useful for most any RPG not just mystery games
  
• Mitlanyal (The Book of the Gods), Swords & Glory Vol. 1 (Tekumel Source Book), The Book of Ebon Bindings, The Tekumel Bestiary - great presentation of fantasy religion as religion, amazing if dense setting book, chaos demons + drawings in the vein of Clark Ashton Smith & Erol Otus, and plenty of alien beasties.
  
• Gateway to Destiny (QLI) - a whole four sectors of adventure, very good for a 3I campaign
  
• GT: Interstellar Wars - small verse human-centered Traveller without the excess baggage & silliness; we have met the enemy and they are us. Fixes most of what I don't like about the 3I while keeping most of what I liked and the book looks great.
  
• GT: Ground Forces, Modular Cutter, Rim of Fire, & Starports - great flavor for soldier types in scifi, the semi-trucks of space, how to do a sector book, and John M. Ford goodness on the nigh-universal scifi location.

Casey, you are my man!

My favorite supplement I've read in a while is the Requiem Chroniclers Guide for V:tM.
 
It's a great little book. The first section is about running a standard Vampire game, but the next two chapters give you “what if” ideas to really shake things up. For example in the Other (by Greg Stolze) gives example of what if the Beast wasn't a Violent Monster, but a self centered trickster. Justin Achilli does a write up of Vampire without Clans. There's even a game to be played as an operatic tradgedy, where players take on operatic archtypes (the lovers, the crone, etc.) So far, it's my favorite book that's come out for requiem, showing A. How versatile the Storyteller system is and B. how broad a game about Vampires really is.

For d20, Reqiuem for a God by Monte Cook is pretty friggin' fantastic. Same goes for When the Sky Falls, by Bruce Cordell. The former deals with the aftermath of a god's death, and the latter deals with the aftermath of a meteorite impact. Both books cover their subjects with imagination and style, and really cover subjects rarely covered in D&D terms. Two of my favorite d20 products.

Hinterwelt's free online Chargen program.

It's really nice tool.

Unearthed Arcana and Monster's Handbook by Mike Mearls are two of my favorite 3.x support products.  UA is chock full of house rules tweakery and the Handbook taught me a lot about making my own baddies.

The Hypertext d20 SRD is one of the greatest resources for a Dungeon Master.

For older versions of D&D, nothing beats the Arduin Grimoires.

I don't use much supplementary material for non-D&D games.  I consider Supplement 4: Citizens of the Imperium absolutely essential for Traveller.  Mekton Zeta ain't the same without the Advanced Technical Handbook.  Past that I like most games slim and unadorned.

Yeah, Unearthed Arcana is my favorite D&D 3e book besides the core. Very useful for tweaking one's game to taste.

D20 Toolbox, AEG
Magical Medieval Society, Expeditious Retreat Press
From Bone to Steel, Monkey God Enterprises
Caffeine

Quote from: jrientsFor older versions of D&D, nothing beats the Arduin Grimoires.

I consider Supplement 4: Citizens of the Imperium absolutely essential for Traveller.

Quote from: SosthenesCaffeine

QFT QFT QFT!