I generally have two knives, but not to use one as a "beater."
In one pocket, I usually have a one-hander for tough jobs, or for when I only have one hand to get out my knife (happens at work pretty frequently). Today I'm carrying a Spyderco Paramilitary.
In my back pocket, I usually have a slipjoint of moderate size (today, it's a Queen Copperhead). This one gets used for food, opening boxes, indoor situations where a smaller knife is appropriate.
Then again, my job is about 50/50 office time and boat time. In the office I use the slipjoint more, and out on the boats I tend to use the one-hander more often.