I'm thinking probably one of the following:
Colt 1911 Witness or Swiss Arms version
Beretta 92 or Taurus variant
Sig x5 p226
Luger KWC build
Other?
Reason: I suppose everyone should have at least one of these, even if they are bb.
I would prefer one with the co2 and bbs in the magazine.
Wouldn't get shot much though.