I wouldnt recomend this unless you know you can take down a certain powerfull creature and really want a secound knife for dual wielding. The dagger he has now does 7 in base dmg (I asume its base dmg) and the knife you get in that quest only does 6.
Yeah, that's right. NVM - I was looking at the Description Card screenshot that listed 15 as the damage. I guess whoever took the screenshot had some skill in One-Handed.

One thing no one has mentioned yet, of which you should be aware, is that bow "weight" is tied to draw time. Light bows draw and therefor shoot much faster than heavy bows.
The only exception is the Daedric Bow, but the speed difference is only 0.06 faster than the Ebony. Plus, you probably won't find a Daedric Bow and would have Smith one.
The bows are at the bottom of this page:
http://www.uesp.net/wiki/Skyrim:Bow#Bows