I think it's safe to say that we all love printables. They are great for last minute projects and they just feel more personable, especially printable cards. I don't remember the last time I bought a store-bought card because they just don't feel special. Canon offers a plethora of cute and clever printables. Their gift and card section can prove to be especially useful when you're in a pinch for that last minute gift or card.
Printable cards are great because they are unique (chances are, your friend won't give the same card!) and they are hand-assembled by you - and that always adds a personal touch.