I misspoke up above regarding the rail mount lights for a handgun. There is the Streamlight out there that is quite good also, I should have thought of that as I have two of them, an M3 and a TLR-1. The M3 has a version with an integral laser that is named the M6. it lists for something in the $250+ range while the M3 is around $100-$150. These M series have halogen bulbs and throw a kind of harsher, yellowish light. I think they cast a beam further than the LED but won't swear to it. The TLR-1 is an LED light and it appears to be softer on the eyes of the holder though not on the recieving end. It is much whiter in color, almost a bluish tinge, but doesn't seem to extend the rays as far as the halogen. I picked mine up for a little under $100 this summer. I believe the TLR-3 has an integral laser and runs correspondingly more expensive. The Streamlights are a fair bit cheaper than Surefire and I am sure will do well for the majority of uses one will put them through. At least I can buy a couple for the price of one Surefire and replace them as they go down.
As FuelBurns2 says, $469 is a typical price on a black or olive XD9 or 40, Bi-Tones and Earth Tan go for more.