Bang for buck, the Celestrons are hard to beat. Here is a guide from OpticsPlanet
I used to research my own purchase.
I ended up with a Pentax 80mm ED, but mine does triple duty: nature watching, low level astronomy, and target shooting. It allows me to use a variety of astronomical eyepieces, and is rather rugged.
A few other things:
- Don't neglect the tripod / mount. The best scope can be rendered useless if the mount isn't solid.
- Eye relief is important, especially if you wear glasses.
- Sometimes what you are paying for is durability as well as good glass. For example, the Celestrons have just as good or better glass than many competitors in its price range - however, they will require a bit more care in handlling.