A Dobsonian reflector telescope is generally considered to give the most bang for the buck, but I've always had trouble with seeing through them and there are two other issues that make them problematic for me. First, the optics are not enclosed and unless you're going to use the scope only indoors, in a dust and lint free environment all the time, (no pets) it'll require frequent cleaning. Also, they're heavy and large and not very portable.

I've had a Meade ETX 90 EC Maksutov-Cassegrain scope for about 8 years now and it's served very well as both a casual night scope and also as a terrestrial spotter with it's lowest magnification eyepiece. I like the Mak design because it's essentially a short, fat can that'll fit easily into a briefcase sized carrying case and can be used with a small portable tripod when necessary. I can take it hunting or camping with ease. It also has computerized tracking and a built in and upgradable star finder program that will "go-to" deep space objects. There are newer and larger versions of this scope now that have built in GPS and are much easier to use, but I don't use the computer features that often and it's always been adequate for me.
One thing you'll find yourself doing pretty soon if you find you're really into your scope is buying more eyepieces, and they can get pricey. I've got eyepieces that cost almost as much as the scope originally cost.
Orion makes nice scopes, and they tend to be less expensive than Meades. If I'm not mistaken the computerized xt10 retails for about 700 dollars, so 500 may or may not be a great price depending on extras you're getting with it and it's condition. Good luck!

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