I used to have a PDA. Then I had a Day Timer. I even tried one that was 8.5x11 in size so I could punch holes in any standard paper and add it to my planner (like meeting agendas, presentation notes, etc.)
They all left me feeling like Goldilocks. None of them was "just right."
I even tried to make my own. I designed my own pages for tracking the things I was interested in like book release days and book series and craft shopping lists and to do lists. That didn't even do it.
This year I bought this:
Ridiculously simple, right? I noticed this at the bookstore last year when I was working a less intense job because I thought the Sudoku puzzles would be something I could do in my down time. This year, when I actually bought it, I don't have time to do puzzles, but the simple to do list format is working perfectly. Every Friday I tear off the weekend page. Then I pull off the Monday through Friday pages and staple them together. Part of my Friday routine is to fill out a to do list for our weekend and start my lists for the week ahead.
Recently I added to that a system described by Michael Hyatt for managing your workload. Items that are both urgent and important are marked with an A. You do those first. The important but not urgent items get a B and you do those next. The urgent but not important are Cs and things that are neither urgent nor important are Ds.
This is by far the simplest planner system I have ever used, but it is exactly what I need right now.