My personal fave 9mm weapon is the MP-5 (maybe because I'm a Stargate nut) but I prefer the .45 M-1911 over the M-9 Beretta.

H&K made a new MP-5 called the PDW (personal defense weapon), it's a smaller MP-5 with folding stock, folded up it's not much bigger than a large pistol (like desert eagle), it's designed for pilots and aircraft crew.