you could go a few different ways, honestly it sounds like a big survival type knife might just be a pain in the ass on the trail because you'd mostly be using it for tasks which a pocket knife could do - i would recommend you get a quality folding pocket knife that locks back which is made of a good grade of steel so it doesn't rust, maybe with some serration on the bottom part of the blade so you can chew through rope easier, the only con of serrations is that you'll never be able to sharpen it.
for chopping branches you could get a hacksaw (not a home depot type, you can find some good brands that are much lighter), or an axe, again not a heavy home depot wood handled type
for pocket knives i recommend kershaw and spyderco
if you're dead set on getting one knife that'll do it all esee and cold steel makes some good ones, in particular i'd recommend these models:
http://www.eseeknives.com/junglas_machete.htm
cold steel gurkha, probably the best knife for chopping branches ever made
http://www.coldsteel.com/sanmaigurkha.html