Hunting:
I carry a Case folding knife with two blades. I also have a Buck belt knife I like. I plan to retire my Case to the gun cabinet this year to pass down to my kids. I prefer the folding knives to fixed blade. I recently caught a Gerber locking belt knife on sale at Cabalas that will allow me to switch between a knife, bone saw, and gut hook. Looking forward to using it this October during Colorado's first Elk firearm season. I’m a little worried about the quality of the steel in the Gerber but for the price it was worth a try if only for one season.
Car:
I have a Leatherman in the glove box of every vehicle we own. Never know when you may be caught in a jam and need a good knife, pliers, saw, or bottle opener.
Camping:
Although I use to camp and backpack with a Swiss Army Knife, I have switched to the Leatherman style and haven't looked back. I have both the Leatherman name brand and several non-name brand Leatherman style knives and can't tell the difference. The Swiss Army Knife is a good knife and I know a lot of people that carry them. For me the tools on a Leatherman type knife are more useful than on the traditional Swiss Army Knife.
Get a good sharpening kit. I grew up using a stone or leather strap. While they both get the job done a good sharpening kit is worth the money and extra time it takes to use.