Personal Opinion only:
For daily carry, I go with iron sights (fiber optic front). That's on a full-size gun, however. I am a fan of putting a laser on tiny guns with poor sights, however---guns like the LCP, PF-9, and a j-frame are all ones that I think can benefit from a good laser. I agree with SFG that green is the way to go, if you are going to have a laser for daytime use.
...that being said, if you are going to be carrying a gun with a weaponlight on it, my HUGE preference there is for a light/laser combo like the TLR-2 instead of the TLR-1. If you ask anyone who has shot a night shoot, having a weaponlight on the gun is great for being able to keep both hands on the gun---but you are simply going to be MUCH more accurate and quicker with a laser with it also. (First found that out at the Rogers Shooting School several years ago. During the night shoot, those of us with light/laser combos SIGNIFICANTLY outshot folks with just weaponlights.)
Summary:
Gun with good sights: Don't see the need for a laser.
Small gun with poor sights, most likely shot with one hand from a strange position: Laser can be helpful
Gun with weaponlight: Get a light/laser combo.
As someone else said: If you are thinking of putting a red dot on it (like an RMR) that's a VERY different question.