I like this challege, its simple and realistic. Im very sorry to hear about your job. Good Luck finding a new one that you enjoy.
Now I have a few knives and I carry two at a time ALL the time, so carring just one would be a hard thing for me. But in the spirit of the challenge I would pick a Benchmade Griptilian 550HG, I have one of these knives with a satin plain edge blade and Im trading for another one with a black combo edge blade. I have three favorite folding knives that I USE: ZT 303, ZT 350SW, and my Benchmade Griptilian 550HG.. and the other two are above the price limit. But the Griptilian is still one of my top all time favorites. The one I actually paid for cost me about $79 IRRC after opting for rushed shipping and taxes. I carry this knife all the time but its always paired up with my ZT 303, so Ive never actually carried it by itself.