The Modern Service Weapons site had a nice article on 3-dot and night sight configurations.

I have no problems with weapons lights or night sights, but prefer the Heinie Straight 8 or 10-8 Performance versions. I carry concealed 99.9 percent of the time and prefera hand held to a weapons light.

I agree witht RPG that you ought not to take chances with a pistol inside a bag without something g covering the trigger.