Useful Game Design Resources

Here are some VERY useful links on game design. I got the list from here. You should visit that web site too - they have more stuff like articles on production and productivity, and even the actual design documents from games like Doom.
In brackets after the article name is the source... please note that you have to register with GamaSutra (free and instant) before you can read their articles. It's worth it though.

• Adapting the Tools of Drama (GamaSutra)
• A Primer for the Design Process - Part 1 (GamaSutra)
• A Primer for the Design Process - Part 2 (GamaSutra)
• A Primer for the Design Process - Part 3 (GamaSutra)
• Applying Risk Analysis to Play-Balance RPGs (GamaSutra)
• Artificial Intelligence in Game Design (AI Depot)
• Behavioural Game Design (GamaSutra)
• Better Game Design Through Cutscenes (GamaSutra)
• Beyond Psychological Theory: Getting Data That Improves Games (GamaSutra)
• Building Character: An Analysis of Character Design (GamaSutra)
• Chopping Down the Tech Tree: Perspectives of Technological Linearity in God Games - Part 1 (GamaSutra)
• Chopping Down the Tech Tree: Perspectives of Technological Linearity in God Games - Part 2 (GamaSutra)
• Collaborating in Game Design (GamaSutra)
• Constructive Politics in a Massively Multiplayer Online Role-Playing Game (GamaSutra)
• Creating a Great Design Document (GamaSutra)
• Dynamic Problem Creation and Adaptation Techniques I - Basic Introduction (Kralizec.net)
• Designing Design Tools (GamaSutra)
• Emotional Content in Computer Games (Paranoid Productions)
• Evolutionary Design (GameDev.net)
• Five Ways to Sneak Originality into Your Game While Management Isn't Looking (shown on GigNews)
• Five More Ways to Sneak Originality into Your Game While Management Isn't Looking (shown on GigNews)
• Fun is Fine: Toward a Philosophy of Game Design (Joystick101)
• Game Design: Secrets of the Sages - Creating Characters, Storyboarding, and Design Documents (GamaSutra)
• Game Design: Theory & Practice (GamaSutra)
• Humour in Games (GameDev.net)
• I Have No Words & I Must Design (Interactive Fantasy #2)
• Level Designing Rogue Leader (GamaSutra)
• Level Design Resource Guide (GamaSutra)
• Lock Mechanisms in Game Design (GameDev.net)
• Lost Along the Way: Design Pitfalls on the Road from Concept to Completion (GamaSutra)
• Mobile Games Resource Guide (GamaSutra)
• Motivations in Games (GameDev.net)
• On Gameplay (GameDev.net)
• Removing the "Tech" from the "Design Document" (GameDev.net)
• Replayability - Part 1: Narrative (GamaSutra)
• Replayability - Part 2: Game Mechanics (GamaSutra)
• Techniques for Achieving Play Balance (GameDev.net)
• The Anatomy of a Design Document: Documentation Guidelines for the Functional and Technical Specifications - Part 1 (GamaSutra)
• The Anatomy of a Design Document: Documentation Guidelines for the Functional and Technical Specifications - Part 2 (GamaSutra)
• The Case for Game Design Patterns (GamaSutra)
• The Designer's Notebook: Death (and Planescape: Torment) (GamaSutra)
• The Designer's Notebook: Positive Feedback (GamaSutra)
• The Game Proposal (GamaSutra)
• The Right Decision at the Right Time (GamaSutra)
• Turning a Linear Story into a Game (GamaSutra)
• Using Low Level Stories (GameDev.net)
• Virtues of a Graphical Interface (Paranoid Productions)
• What's Your Perspective? - 1st vs 3rd person perspectives (Paranoid Productions)
• You Got Game - turning an idea into a design document (GameDev.net)
• Your Audio Design Document: Important Items to Consider in Audio Design, Production, and Support (GamaSutra)