My top five are:
1. Axis lock for it's super smooth ease of use combined with what I think may very well be one of the strongest, most reliable locks available today.
2. Hogue Button lock for reasons similar to the Axis lock. It's super smooth and reliable with good ease of use. Although not quite as strong as the AXIS certainly strong enough for any cutting task.
3. Triad lock. Although not normally as smooth as the above locks and often requires two handed closing when it comes to shear strength and reliability it can't be beat.
4. Sog Arc lock. Super smooth, strong reliable lock. Good ease of use again similar to the AXIS lock.
5. Modified liner locks of various manufacture. Classic, smooth blade deployment with easy one handed opening and closing. Not as strong as the others but I find a pleasure to use. Just something about a good liner lock that will never go out of style.