I have stood behind a machete for literaly thousands of miles in the past 25 years as a Land Surveyor here in East Texas. The Ontario Knife mentioned earlier is an excellent choice. Barteaux is also a great choice.
Barteaux Machetes Product 1 I always liked Blackie Collins, as the seemed to have the best balance, but can't find them anymore.
I would recommend the 22" with knuckle guard. The 24" models seem to bend a little too often for my taste. The guard takes a little getting used to ( not for the limp wristed among us

), but keeps it from flying out of your hand when you get sweaty.
When you factor in the free shipping, this is about the best price I have found, in fact, I just ordered 4 of them.
Ontarioï½® 22" Improved Machete - Heavy Duty
We use them for every thing from briars and honeysuckle to 12" oaks. The larger trees we cut by using two men taking alternating whacks. Cutting involves a little physics, but it aint rocket science.
The method that works best for me : Being careful, put some tension on what you are cutting. Using your free hand ( I use a 1" square lath as an extension of my hand ) bend what you want to cut to the left. Take a solid downward stroke at about a 45° angle toward the left at the base on the right side. 2"-3" trees should come down in one whack. For cutting limbs out away from the trunk of the tree, stand fairly parallel to the limb, cut either back toward the tree or away from the tree, so that the limb can't swing away, but has to absorb all the force. Whenever possible, cut limbs up close to the trunk for best results. For briars and honeysuckle, I take that 1"x48" square lath that I carry and wind it up in the vines so that I can put some tension on them while I cut. Takes a little practice, but works well.
Bruce
RPLS 5781