Streamlight is absolutely awesome. My Father carried Streamlight on the job (a handheld) for many years, we then bought several handheld Streamlights I use on and off a daily basis, depending on what I'm doing/what I need etc.
Their deal is the highest qual for lower prices ... Surefire is sort of the Bling Brand, Streamlight is all about top quality for a more value.
Their weapon lights are basically the TLR-1 series, full size light, TLR-2 which is full size w/ red laser, TLR-2G w/ green laser , TLR-3 which is a compact sized light (for smaller than full sized frames etc.) and TLR-4 w/ red laser, TLR-4G w/ green laser.
There are of course specific submodels like the HL/HL/S/models etc. They make great great stuff.
Just to throw this out there- there is a light @ Walmart called the Nebo PROTEC Elite HP190 ... it's $39.99 for a 190 lumen light w/ strobe feature. I bought one for the M&P22C .. but it just didn't like the rail, it couldn't stay grabbed on that gun. When I put it on it was fine, but during firing it would come off, so I had to return it. Otherwise it was a fine light for 40 bucks, I recommend it!