Man, the DE .50 is NOT what you'd want for real. Just take a look around at what handguns real life military are using. I shoot a lot and own a lot of diff guns. I've shot just about everything out there. The DE .50 is fun, but not what you'd want in a real life-or-death situation.
The 1911 is definitely a great option, but capacity is a drawback. Don't get me wrong, it is my most favorite handgun to shoot (the Hi-Power is my 2nd), but I want something with more capacity and something that can take things like tac lights, etc.
I would go with the HK USP in .45. Again, it may not be my "favorite" gun, but its what I'd want next to me in a crisis. My second choice would be the Springfield XD45. It fits my hand better than the USP, but the USP is just much more solid than the XD.
It would be really great to have pistol unlocks in the game. I like using the pistol in game, but its hard to survive w it. That, and the physics for accuracy is completely f'ed for pistols in the game.