http://www.leatherman.com/multi-tools/full-size-tools
The quintessential McGuyver tool. I've carried one on my belt for 20+ years. Use it many times throughout the day. Buy one and you'll wonder how you got through life without it.
I've had many of the Leatherman models, and the
WAVE is my favorite. The Charge is a good model, too. The Surge is too big and heavy to carry on your belt all day. Had one, gave it away, and got another Wave.
I've had other brands, but none compares in quality and ergonomics to Leatherman. A Leatherman will take many years of abuse, but it won't fly back to you if you lose it.
ps. The Wave comes with a heavy-duty leather holster. Many of the other models are nylon with velcro, but I prefer leather with a snap.