The glory of the Hipster PDA is that you can carry your planner in your pocket. Lists, calendar, capture device--all in one 3' x 5' x 1/3' package.

And you can mix and match. After a lot of experimentation, I've finally settled on a 2nd project support Hipster, organized alphabetically by project. I carry this in my bag during the day, take it out and put it on my desk next to my main hipster when I get home. (The main hipster travels in my pocket).

If I'm heading out without a bag, then I simply pull out whatever project support cards I plan on needing during the day and put them in my main hipster. So I can travel as heavy or as light as you want.

And, what makes this technology superior to an electronic PDA, is that you can always keep a loose 3 x 5 card handy for capture--so you don't have to pull out the whole hipster.

The downside: for the whole system to work, you need a pretty rigorous processing regimen. But since this is an important part of GTD, I prefer a technology that actually forces me to process.