I use a wiebe replaceable blade knife (similar to havalon) and for blade replacement the pliers on a Leatherman works well, you won't cut part of your finger off that way
I have tried a bunch of stuff. Fixed,folded,replaceable.....and these are my favorites to actually use. That benchmade became my favorite fixed.
The gerber is hard to beat for the money. And the other tool isn't a must but it's light and is so much faster for me to open a hide.