A laser isn't really anymore useful in lowlight than night sights. Where a laser really shines (haha!) is when you have to shoot from an unconventional position, when you can't see the sights, etc. I have a light on my HD gun, because target acquisition is absolutely paramount in that situation (don't want to shoot a family member stumbling around for a drink of water) but I don't see much need for a laser in most cases.
Maybe it's just me, but laser sights have always seemed to be a bit gimmicky. It's a crutch to proper sight picture. It's certainly nice to be able to have a point of aim if you can't use the sights for some reason, but in most SD/HD situations, I can't see many times that situation will arise.
Lasers, no. Mounted light + Night Sights, yes, yes, yes.