I keep wavering between an electronic calendar (iPhone), and a paper planner. I feel like using my phone at work can distract me, or make me look like I'm not paying attention (such as when I'm scrolling through my calendar during a meeting). However, I get tired of lugging a paper planner around all the time (I can't write enough info in tiny ones to make it worthwhile).
This year (2010) I used both a paper & electronic planner, and I don't recommend it unless you're dedicated about making sure both are in-sync.
What do you use? I think I want to go back to paper, but after reading a lot, I am overloaded with options.