Alignment system very useful for playing?

[Math_Mage]

Personally, grappling with D&D's alignment system (yes, including all the irritating forum arguments that crop up) made me a much more sophisticated consumer of ideas about ethics. That alone makes alignment useful from my perspective.

Useful for playing? Well, I'm one of those beginner players Rich was talking about, and I've never actually run a full campaign, let alone a full campaign where alignment was a significant factor, so alignment has primarily been useful for character creation. Making a decision about what alignment my character was going to be helped me develop his/her personality and backstory, because it gave me some first-order constraints to work within.

Of course alignment is a crappy substitute for thinking about your actual character, just like looking at a magnifying glass is a crappy substitute for actually looking at an ant if you're trying to learn about the ant. But if you look at the ant through the magnifying glass, you'll find it useful. Alignment is not a substitute for character development or roleplaying, it's a lens through which to view those things.