Asking for a light run by a single CR123A implies that you want something small. This leads me to recommend the 4Sevens Quark Mini 123. Go with the "X" version (Cree XM-L) if you want wide beam or the plain one (Cree XP-G) if you want a bit more throw. Both are available in Cool White, Neutral...
The JetBeam BC40 is a great allround flashlight with good throw that utilizes 4*CR123 and XM-L T6 for a reasonable price. It's also available in Neutral White. I keep one by the front door in my country house.
You can read the review here...