I disagree with Anthony Cheeseboro (and Paul Work who agreed with him) when he mentioned that the Spyderco Mouse, Co-Pilot and Navigator were good below 2.5 inches tactical knives. Their blade design and shape really serves best for cutting materials such as cardboard boxes, and the mouse looks more like a skinner. I am more partial to blades which are spearpoint or similar, and a little larger than the knives mentioned above.
I agree with their selection of the Spyderco Dragonfly. This knife looks like it packs as much blade as possible on a little knife, and also looks like it can do substantial damage when thrusting. Also, it looks unobtrusive when closed, since the handle is small yet ergonomical. Once you deploy the blade, you feel like you hace a Calypso Jr. on your hand! If I go to clubs or anywhere else where they (incompetently) check for weapons (except federal buildings or other high security areas, of course), I always carry mine in my back-pocket, hidden by my wallet in front of it (in case the bouncers pat me down). I've never been caught with it.
If I'd pick another Spyderco around this size, it would be the C37 FRN Michael Walker lightweight. This little knife really packs a nice, big-looking 2.5-inch blade, and also looks like it could thrust/slash very effectively.
Both these knives are very inexpensive at $30-$40 from internet dealers, yet are high-quality pieces. Blade is AUS-8, which might not be top-of-the-line, but isn't too shabby for a small folder.
-Flood