My brother told me I was crazy when I bought a package of 12 or so post-it note pads earlier this year. I'd never use them all. I didn't need anywhere near that many. Slowly, I've scattered these things around the house and now there's always one near when I need it. And believe me, with my scattered brain, I always need to make a list of something to remember.
Now I've hit on another idea. I'd been thinking of getting a bulletin board, but today I realized that if I just stick all my post-it notes on the door I will see them as I leave, and can even grab the appropriate note or notes for whatever excursion I'm making. This is great; two notes so far, going on two hundred I'm sure.
This beats PDAs all to pieces. If I had a PDA I'd spend all my time looking for it. There's literally a post-it pad nearby almost everywhere in the house. I scoff at your high tech solutions!