>I used to keep a larger, more generic "spark file" but I found it got to be too big to navigate. So I throw away more ideas now, and only write down ones that have serious merit, placing them in specific files instead of a "kitchen sink" catchall file.

You could also use Devonthink Pro, as described here: http://www.stevenberlinjohnson.com/movabletype/archives/0002... as a placae for all this material, including the "rule to live by" file. DTP might help you find connections between ideas that you didn't realize existed.

EDIT: Mental note: Read article before commenting. You already know about DTP! Sorry.