I have a 7x50. It is not light but it is very comfortable to hold and look thru all day. To me 7x is more than enough zoom for just hiking use. And 50 is very bright, you might be able to go 40 to save some poundage. The smaller ones are nice for a quick zoom, but if you need to use them for a long period of time I suggest you get a bigger one.

Don't go too cheap on it. Since it's going to your pack it will be thrown around so I don't think a $15.00 binocular will last.