MP-5.
I've been carrying one since we transitioned away from the uzi in the late 80's. Others on the team carry the P-90. I did some testing on a new experimental weapon last year, but by the time the Government makes the switch, I'll be retired and dead.
I just wanted to offer a comment on flashlights. While I agree with the power to blind your adversary and certainly to identify your target, you need to be very careful about how to handle your flashlight so that it doesn't get you killed.
First, and most importantly, never hold the flashlight in front of your body, or attach it to your weapon. I know you see it on TV all the time, but don't do it unless you're willing to practice room clearing for several hours a day. If you hold the flashlight in front of your body and confront an armed attacker, he will fire at the light and catch you in the chest. Hold the flashlight in your off hand, as far away (out to the side) from your body as you can, slightly in front and above you so that you don't sillouette yourself with your own light.
Second, don't turn the flashlight on and leave it on as you clear your house. Get one with the push button on/off. Turn it on for quick flashes, look at what you want to see, turn it off and MOVE. The bad guy will fire where he saw you last. Don't be there.
If your situation ends in gunfire, shoot and move, shoot and move, shoot and move. Move laterally, not forward and backward. Do not stand flatfooted and fight it out. Keep moving. Learn the difference between cover and concealment and use available cover whenever possible. Only leave cover if you've identified better cover elsewhere. Always point your weapon where you are looking, just like you were pointing your finger. Don't point the gun at the ceiling or floor like the TV detectives. By the time you acquire your target that way, you'll be screwed.