A .45 ACP Luger.
The next best thing, a .45 ACP Broomhandle Mauser. This one I've got, and side by side with my Bolo 7.63, it makes the Bolshevik Special liook like a pocket pistol.
Big Honkin' Colt New Service revolvers look like a revolver should look. (N-frames notwithstanding!)
Big-bore long-barreled Mateba auto-revo's are mucho-cool also.
The Automag III, and it's bigger, fatter brother, the Automag V, are both really cool LOOKING guns. AMT's are AMT's however, which robs them of some of their presence. MY A-m-3 is profoundly reliable, however, and one of my all-time favorite guns.