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I use iCal and my iPhone.

I started with a Day-Timer, went to a series of PDAs mostly Palm devices and then smartphone.
 
Before "HAL", I used a day-timer for scheduling my work-load/appointment/etc, never a PC program.

Since, 3+ years, it's been iCal all the way, with post-it's on Dashboard for purchase reminders, notes, etc.
 
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