My daily carry light is the Streamlight Protac 2L-X. I use the streamlight rechargeable battery pack, unless I'm in the field, then it's CR123s. The only issue I've run into is the pocket clip wearing out.
I've also got a surefire stiletto for special occasions or when I wear skinny jeans. It's thinner than the Streamlight, but I can't swap the batteries and it costs more.
I've given away two streamlight wedges because the pocket clip screw kept stripping when I went to flip the side. I wear my light on the left side. It had a good light and the best form factor (thin) and was affordabl
I also carry a stylus pro as a back up light. Great light, I gotta see if I can get a red LED version. My previous Stylus was a red one, good for when you only need a little light.