I am also a knife fan.
Stay away from cheap knockoffs, but also ask if something is really worth it before spending upwards of $150 on a knife. There are some good knives out there with unique features worth that much money, but they are the exception and not the rule.
For folders, I am a really big fan of Cold Steel, and there is a Recon 1 with the half-serrated spear point in my pocket as I type this. The "Proof" and "More Proof" videos are worth watching although "More Proof" is overly long.
If you are limited to 3", the Benchmade Mini-Griptillian is an excellent choice. I have two, one set up for each hand.
Features to look for:
Generally, avoid liner locks. They wear out quickly. I might make an exception for Cold Steel because of their Proof videos.
Rpcker bar locks are simple and strong, but provide the most resistance to thumb opening. They are generally a good choice.
The Cold Steel Ultra Lock, Benchmade Axis Lock, and Spyderco ball bearing lock are among the best locking mechanisms I have seen.
I prefer tip-up carry, for fastest access from the pcoket.
There is a lot of hype about blade steels and styles, but it is mostly just that. A "Tanto" point is nothing like a historical Japanese Tanto knife, and would actually penetrate less than something like a spear point. A version of 440 stainless, AUS8, ATS34, or 154CM are common, reasonably priced choices. Worry a lot more about legality of carry and speed of access than having the latest blade steel.
Emerson's wave opening feature is really nice, but will tear up pants relatively quickly, and see my earlier comments about liner locks.
