Curt's Capturing your idea-gems lead me to several good articles about snippet-keeping. Here's how I tackle this challenge...
It will come as no surprise to regular readers that I use Tinderbox to gather, record, and mine my ideas longer-term. As this article from Innovation Tools points out, if you use an analog method of capturing notes, eventually you'll want to move them into your computer. For me, that mostly means Tinderbox.
I say "mostly" because I've also been experimenting with a public store of conjuring-related thoughts and ideas, using the very software you're soaking in now -- TypePad. My other site is working out OK for me, but I haven't been doing it long enough to have any conclusions or cogent thoughts about this approach. I'll write more about that when it starts to gel.
But we still live in an analog world, so for those "fleeting thoughts" that I just have to capture when away from my computer, a "pocket briefcase" of index cards is indispensable. I use one of unknown manufacture, but it's similar to these from Levenger.