Never left paper
I used to use a Palm Pilot (wouldn't it be great if they got that band back together again?) for calendar and contacts. Now I use a Droid and cannot imagine entering all of my contacts each year! I also like the Droid and Google calendar.
But I find that I cannot think and type as well as I can think and write/highlight/erase/scribble etc. Brightly colored file folders neatly labeled in a drawer have never lost their appeal. I love recycling Dilbert cartoons from the daily rip off calendars to use for NAs.
So I've never gone over to the (dark) electronic side.