Currently available liner lock models would be the Military and the Captain. There is also a sprint run of Bom Lum Chinese Folders in ZDP-189 due out shortly. The Howard Viele II and the Ken Onion SpyKer, although discontinued, are still easy to find. Current framelocks would be the Cricket, Spin, and Volpe. Another framelock would be the Warren Thomas Karambit/ Like the Viele and SpyKer, it has been discontinued, but is still pretty easy to find. However, it is rather specialized.
Lockbacks, and the Spyderco front lock in particular, are stronger than liner locks. Many people also feel they are more reliable. They also are totally ambidexterous, another plus to those of us who are left handed and to those right handed individuals smart enough to realize that they may not always have the use of their "strong" hand.
Spyderco also has a number of models with their compression lock, some liner style, some framelock style. They are stronger than conventional liner and frame locks, and, while handed, are less difficult to close safely left handed.