Lightweight knife?

I was wondering if anyone had any suggestions for a lightweight folding knife. I'm looking for one to throw in my pack for hiking. The last time I went I grabbed one with about a 3" blade but was pretty weighted. I'm planning on a longer hike and so I'd like to slim down my pack weight but still would like to carry a decent knife.

 

It looks like Benchmade 531 is only 1.8 ounces! Which is nice!

I would want folding and something I can any camping related type of activities. I'd prefer just to bring one knife. I've debated on a multi tool of sorts but those are heavier and I'm just not sure that I'm going to need all that it can do. The pliers would likely be nice though....but the knives on them generally aren't very big either

 

Might be a dumb question but what makes a knife "good"? The Benchmade 531 is over $100 and then I found a Buck knife that is 1.7 oz at only $25. Obviously, you'd want it to be sharp but there has to be more value somewhere else because there's only so sharp you can get.