In my opinion your requirements lean towards something built on a Kalashnikov/AK action. If there is a more reliable weapon out there I haven't heard of it. Plus they are available in both .223 and .308, are pretty light, and maintenance is a snap. It takes less than a minute to have it completely apart without tools.

You can get cheap AK's for around $400 everywhere. Continuing up the ladder Arsenal, Inc. and Krebs both make top end AK clones for around 1k. With your budget I would personally look real close at a Finnish Valmet M62, M71, or M76. They are Kalashnikov based rifles and take the legendary AK toughness to the extreme. In my opinion they are in a league of their own. Greatly improved sights, better barrels, fine craftsmanship, ect. Gunbroker.com has them all the time for 1k - 2k in .223 with the .308 ones going for a bit more.

I do see the advantages of using a bolt action for bugging out though. Being 500 yards away hiding out with that .300 is in most cases going to be a better choice then trading lots of lead with one or more people closer in. I am not to talk you out of getting a magazine fed military rifle though! There are situations where nothing else would do. Besides, they are flat out fun to shoot!