There are so many good knives out there that would fit your bill. I'm biased toward Benchmade and a few others, and I like their Axis lock. I think pretty much anything a guy chooses from them (blue or black class) would suit him well as a backup knife in a tough situation.

With that said, the Ritter RSK1 gets good reviews whether in this forum or another. I've yet to hear an ill comment about the knife. I don;t own one only because I procrastinate each time I'm in the market..... and I'm partial to fixed blades anyway so I don;t buy too many folders.