What is a CT laser?
I am putting TruGlo TFOs on my XDM 9mm; I figure being able to aim under all lighting conditions is a no-brainer for any weapon.
However, as someone pointed out to me, the absolute best investment for a home defense weapon is a flashlight, because if you can't see your target (and friendlies!) then fancy sights and lasers are useless. Thus I'll be picking up either a rail-mounted SureFire or Streamlight as well.
The new green LaserMax Uni
lets you mount a light underneath the laser which seems like a sensible approach. Not cheap though.