Re: Flashlight/Laser Combination
Have you considered the Streamlight TLR-2S? I have a Streamlight TLR-2 without the strobe that I'm pretty happy with; it's been on a number of different weapons (9mm handgun, AR-15, .40 S&W handgun) and held zero fine. I think Viridian and Surefire also make well-regarded laser/light combos; there's also a Crimson Trace VFG I've been meaning to get my hands on to try out.
In the serious professional equipment range, you're going to want to go with the above advice I'd say - a Laser Devices DBAL, OTAL, ITAL, etc. up top and a separate light, probably a SureFire since that seems to be all the rage these days.
Edit: Worth mentioning the TLR-2 has a TINY, counter-intuitive little toggle switch for changing between laser/light/both mode - the KISS value in having separate systems is definitely there.