There’s a lot of multi-tools out there including Leatherman, Gerber, and Buck to name a few… I personally like the older Leatherman Wave. It’s very ergonomic and comfortable. It has a lot of tools on it including a metal file, saw, knife, scissors, screwdriver, pliers, can opener, wire stripper, and other tools that you may need along the way to help you make new tools.
The one thing I really like about the Leatherman wave is that the knife, the saw, the file, and the serrated knife are all accessible without opening up the pliers and they also lock into position which keeps you from nicking or cutting your finger if you’re going to use them to to pry something open… I’ve seen the larger ones and the smaller ones and the wave is the one to buy… I’m on my 4th one… Only because I loose them ;]