How about you post a list of what you have already so we can suggest guns you DON'T have. I'm going to take a shot at it anyways since my collection is pretty varied.
Sig P210
H&K P7M8
1911 from Les Baer, Wilson Combat, or Ed Brown
STI Edge
massive hand cannon chambered in .454 Casull or .500 S&W
I have the top 4 but I am always thinking about getting a hand cannon. I have no real need for it, but then again, how many guns are based on need and how many are based on want?