John Dillinger's Colt government model M1911A1 pistol in caliber .38 Super It has been modified to use a Colt Thompson vertical foregrip, cutts compensator, extended box magazine, and fired fully automatic. It is in the lower left portion of the photograph.
Czech vz61(aka:"Skorpion"); the real R 'n R deal - not the semiauto repro they're selling now. Attach a 'white' light and/or laser and you've got my idea of the ultimate HD/SD nightstand weapon!
There are so many fantasy guns that would be cool to have. Robo-Cops auto pistol or for really terrifying looks Alucards Hellsing Arms 454 Casull Auto would be really cool.
But in the way of real fire arms, I would love to be able to own a Beretta 93r or a mini-gun.