The folks at the Unclutterer weblog are serious about getting birthday cards to loved ones on time. In addition to using Plaxo to capture and get reminders about whose birthday is when, they pre-buy cards:
In addition to a birthday reminder system, I also purchased a card organiser. At the start of the year, I print out a birthday list from Plaxo, buy cards for all of my family and friends in a single trip to the card store, and organise the cards in my organiser.
Personally, Plaxo or other reminder system nag emails asking me to update my birthday so someone else doesn't forget it makes me want to stick pins in my eyes, so I opt for the more subtle approach: find out birthdays the old-fashioned way (face-to-face *gasp!* or via mutual acquaintance) and use a web-based calendar to schedule reminders. But the card organiser with pre-bought cards? Now that is preparation.