The Swiss Tech Utili-key is one useful tool. Or should I say, six useful tools. Here is their official website with more information.
Anyway, if you're looking for a good stocking stuffer for the holidays, I would definitely recommend the Utilikey. I received one last X-Mas and it's been on my key ring ever since. I'm not the kind of guy that carries around a pocket knife with him, so the knife feature comes in handy from time to time. It's actually pretty sharp and not awkward to use.
Here is the Utilikey pictured next to a typical car key. As you can see, it's about the same size. I like to keep my keyring pretty light and this definitely doesn't clutter it up. It really does just feel like another normal key.
Here it is partially opened. I'm surprised at how well it's made. You can't tell from the picture, but it actually locks itself into place when it's either fully opened or closed. There is no chance that it will open in your pocket and fall off (or stab you in the leg).
It's about 5" long fully opened. It is about the size of a ballpoint pen.
As you can see, it has about a two inch knife (semi-serrated), a bottle opener, both a phillips and a slothead screwdriver, and apparently, a micro eyeglasses screwdriver. I've gotten the most use out of the knife and the bottle opener, but the screwdrivers did come in handy a few times.
If I didn't already have one of these, it would definitely be on my wish list.
The Utilikey runs about $10-15 and I think it's a great gift. Keys are something people almost always have with them. It's easy to lose track of a multi-tool or pocket knife.
I have but one gripe about it. To use the bottle opener, it has to be fully opened. This results in you putting a lot of leverage on a skinny little piece of metal with one very sharp end. I've had a few close calls with it slipping off the bottle while trying to pop the cap off. It gets especially tricky after opening a few bottles in relative quick succession, if you know what I mean. Besides that minor issue, I have no problems with it at all.
In addition to its usefulness, it's just plain cool, isn't it?