Both of these are great ideas, especially the bound bow (of course you'll need to perk into conjuration to make it worthwhile). Nightingale bow is good; however, it doesn't scale with you. So, if you get the bow at a very low level it'll be one exotic looking paper weight later on.
If memory serves me correctly the nightingale bow is equal to a glass bow at any level,it's just the enchantments that get stronger at later levels.
If that is the case then the nightingale bow is good to get at any level.I've used regular glass bows through out the game and not had any problems.
The differance between a glass bow and a daedric bow is only about a 4% differance in damage.
Thats not much of a differance and when you consider the fact that the glass bow shoots faster than daedric the damage differance is probably nothing over the course of say one minute.
You may have to use one extra arrow to kill an enemy,wich could be the differance between life and death but that is seldom the case when you are one shooting everything from the shadows with stealth attack critical hits anyhow.
I also happen to find the faster fireing speed of the glass bow much better when faceing a group of enemies.