If you have the pocket book for it, then CD burners are great stocking stuffers. Aside from that, there are regular ol' fashioned CDs. Behind every cold-hearted shell of a guy is his fashion sense. Some guys choose to show it, some don't. So clothes are definite winners.
Guys love to play with gadgets and gizmos of any sort.
Even if a guy doesn't know what it does, he still checks it out. One of the biggest parts of your gift is your card. That's one you'll have to pick yourself. Every guy is different, so make sure to pick one that's good for him. Jewelry is another good gift.