I've heard good things about Saigas as far as reliability goes. They're basically .223, 7.62x39, and .308 versions of an AK-47. I have no experience with them though.

http://www.raacfirearms.com/Saiga.htm
http://www.raacfirearms.com/Saiga_308.htm



Another option is a Remington 7600/7615. These are pump rifles, similar in design to the classic Remington 870 Shotgun. The 7615 shoots .223 and uses AR-15 magazines, which is a nice touch. While not as fast to shoot as a semi-auto it's still quicker than a bolt action and it's about as reliable as a factory 870. I like the design of the Law Enforcement versions best.

http://www.remingtonle.com/rifles/7615.htm

Other than that I'd go with what everyone else here said, a Mini-14 is tough to beat and very commmon.