MolleMan,
$300 is a pretty low price limit if you'd like a new 9mm, and it's really narrowing down your options, can you bump it up a little higher?
If not, a gun like a 709 does make it an excellent choice, and would also be good for IWB carry, where thinness is good, and in the category of new guns, it's about as close to your desired price range as you'll find. Another lower priced 9mm is the Bersa Thunder UC 9mm. It's a bit thicker gun (double stack magazine), but it's still a fairly compact pistol, and unlike the single stack (magazine) 709, the Bersa is a double-stack, SA/DA, hammer fired, de-cocker, W/safety. Those would probably be the two lowest price new 9mm's. For OWB carry (in your preferred paddle holster), you might want to look at the Bersa.
If you bumped your price range higher ($450 to $670 range), the Walther PPS 9mm, and Kahr K9, P9 & CW9 have a similar size and thinness as the Taurus 709, and are equally good for IWB carry (if you ever wanted to carry that way). but as I said, they are currently well above your current price range. The CW 9 would probably come the closest to meeting your price criteria, but I doubt that you'd find one for less than $450, even as some of the lower priced gun shops.
