Keychain Swiss Army Knife
For years I've kept a small Swiss Army knife on my keychain. I use it almost every day, using the scissors probably the most. I lost my favorite which had a pen instead of a toothpick, but recently my backup to that broke (I sent it back under its lifetime warranty, we'll see what happens). So I hastily bought another one, also without a pen (the stylus for my Palm TX has a pen in it, so usually I have a pen wherever I go). I regretted it almost immediately because I quickly discovered that Victorinox has a huge number of variations on a theme at Amazon. First, you can get all kinds of colors. I got a dark green one, but you can get the standard red, black, blue, purple, white, pink, yellow, or gray. You can get translucent colors which are called ruby, emerald, amethyst (purple), citrine (yellow), and sapphire (blue). You can get several colors of tie-dye (orange, green, purple, and pink) or you can also get a flowered pattern called Edelweiss with background in red, violet, blue, lime green, or pink.
Like I said, my older one had a pen. I found out this is called the Signaturewhereas without that it is called the Classic SD. If you get a Classic and swap the toothpick for a red LED light, it is called the Swisslite. If you want both the light and the pen (losing the toothpick and tweezers), it is called a Signature Lite.
You can also get a bottle opener with a Phillips head screwdriver, which would come in handy at times. You can trade in your scissors for a bottle opener (a bad idea since the scissors are one of the most useful things on there) and that is called a Rally. Alternatively you can just add a bottle opener, in which case you'd have a Rambler. Take the Rambler and put a pen where the toothpick goes, and it becomes a Manager. Take out the tweezers and put a light and now you have a Midnight Manager. By this time it is about twice as thick as the Classic, but the same length. This is what Jeb has, but he says he doesn't use the light much, making me think the Manager might be ideal.
If you want something really thin, you can get the metal Alox classic which doesn't have the toothpick or tweezers. It comes in red, black, green, and blue.