1. PM2 (your steel of choice): Just an all-round perfect do-everything knife.
2. Advocate (CQI): Quintessential blade shape; M4 steel; very snappy flipper; thin and pocket friendly especially w/deep carry clip.
3. Gayle Bradley 2: Perfectly proportioned from tip to heel; M4 steel; again quintessential blade shape (Gayle Bradley keeps nailing it).
4. Military (your steel of choice): thin and slicey 4 incher.
5. Spydersaw (discontinued, sadly): Silkys rule the compact folding saw class and I love my F180, however they still don't have anything as compact, thin, light and well built as a Spydersaw. On long hikes I like tossing this and a PM2 in my pack.
I favor open-pillar construction, compression-locks and frame-locks locks the most. My choices are based on what I find most useful in my outdoor recreational pursuits: fly fishing, backpacking, hiking, camping.