The Hipster is the simplest solution to the task of collecting for GTD (Getting Things Done by David Allen). Take the Hipster PDA with you everywhere. When you make some notes, then toss the cards in your 'In' box.
I took the standard Hipster PDA, and modified the 3"x5" notecards, by cutting a 45 degree chamfer in the corner where the clip goes. This way, I can have the binder clip open or closed while keeping the 3"x5" form factor, which makes it easier to stuff in a pocket.
The Cutout is 1" from the corner in both directions, or in engineering speak a 1"x45 degree chamfer.
The mini binder clip I found at Office Depot, as well the graph paper type index cards. I'll post later about my favorite pens..
Now get capturing!