Make the Recipient of your Business Card Feel Special
I'm highly in favor of printing direct dial telephone numbers on business cards (especially if we have one of those icky automated attendants which I confess to having). And some people elect to print their mobile and even home phone numbers on their business cards, as well.
I like to be accessible to my clients and prospects, too, so I can appreciate the gesture, but instead of pre-printing that info on your cards, try this alternate way of sharing that privileged information.
Add a few more seconds to your card exchange process by tell the kind person you are talking with (or mailing to) that they are especially welcome to call you at your personal number. Then write that number: "home 123-456-7890" right onto the card front or back.
This lets you use your business cards in a way that makes someone feel really special...like they are part of a small group of people who have that exclusive access to you.
Another thought...I recently visited Asia (yes it was wonderful) and I'm again reminded of their gentle and honorable custom of presenting and receiving business cards with two hands, followed by the thoughtful study of the card you've just received. (Note: don't ever write on their card or stuff it into your trouser pocket--these things dishonor the card which is considered an extension of the person, thus dishonors the person.)
There is something really nice about this ceremonious way of acknowledging someone. In the US, Europe, or Down Under, you certainly needn't bow or go to abnormal extremes, but do try presenting and receiving cards with a little more panache.
Make the person you're exchanging them with feel a little extra important.