I was "into" RC aircraft when I was younger but had to sell off all my kit years back when I did a long distance move. Since then I've not really had the time or spare disposable income to get back to it.
I'd maybe ramp up to an autonomous system and gain experience with aerial/remote photography with the following steps...
$100 approach... big boxkite, 1000ft or so of line, used canon camera that supports CHDK
http://chdk.wikia.com/wiki/CHDK_in_Brief which allows scripting of camera behaviour, meaning you can robotise that and make it semi autonomous, or adds USB remote trigger ability which could be triggered from the ground with very simple remote lashups. Or maybe do this...
http://www.wired.com/gadgetlab/2009/09/the...r-money-budget/ but tether the balloon and skip the GPS phone. Also might be possible to get slightly fancier if you can get an x10 cam mount and have realtime control and video feed from the ground.
$500 approach... basic radio control system, and build a large powered glider style airplane drone, with electric motor(s), the loiter time could be hours if you can make use of thermal lift, camera system as above, with a bigger lense preferably so you can stand off at a few hundred feet above trees, and the motors will be very hard to hear from below if you even need to use them. With lots of wing area one should be able to build something with a good enough glide ratio such that you can make several passes over an area then climb out away from it, then come back silent again.... some autonomy might be possible to add later if the drone is capable of "hands off" flying, that is that it's inherently stable.
$1000+ approach, this would be the mikrocopter or copter hybrid, a good RC system and the autonomous control systems, 4 motors, lightweight batteries etc will add up... for the blimp hybrid version, I'd consider making the basic structure a 3ft across ring, into which could be clamped one of those extra large size helium fillled mylar novelty balloons on it's side, then you don't have to worry about custom envelopes, should be easy to put another one in it. The rotors would pod off this and I'd mount the camera package on struts slung under the balloon envelope, this should allow quite a bit of pendulum stability and vibration isolation. Really I'm not too clear on all the ins and outs of the concept yet having just discovered the site, but following up all the other builds of them, and googling up mikrocopter quadrocopter etc should get one on the right track... shrouding the rotors as some people appear to have done should reduce tip noise from the rotors/props quite a bit. To get that optimal would take some experimentation though.