In your place, I would come up with a budget concentrated to one knife. But, I would take that budget and purchase the best basic edged tools that budget would allow. I think tools like a hatchet/axe, machete, multi-tool, SAK, small fixed blade knife, large fixed blade knife... are all essential to a proper "gear up". Then, you choose the right tools from your equipment "arsenal" for whatever environment you're going through.
You cannot rely on one knife to do the job. It might do it, but it won't be pleasant for you. Besides, having more than one edged tool is better because it gives you a level of protection that in case one fails, you still have the other.
There is no easy answer. You'll go through plenty of equipment before you realize what works/will work best for you.
Good luck!
:thumbup: