From expirience i'll tell you the break down. But best depends on each person.
M9: w/out stoppin' pwr. F*** it.
USP.45: Good clip size good pwr.
1911 Colt: 8 rounds (1 more than DE.) but almost same power, with less recoil and silencer capable.
DE.(gold) power high recoil and 7 rounds. good if you use "slight of hand".
If you can't shoot..... "USP.45":
If you need silence and can shoot, ......"1911 .45" :
If you aim at thier feet with no lag in the game...... "DE.50"
with last stand and stopping power the "M9" rocks.
hope this helps ur choice.