Today I was also recommended a Diamondback DB9 and a Taurus 709 slim. I am still thinking about size mostly here. The DB9 sure seems like a nice small size. Anyone shoot those?
I bought a Diamondback DB9 about a year ago and like it enough that I bought a second one a few months ago. (If a gun is good enough to have, it's usually good enough to have more than one of!) I love its flatness for carrying, and the grip construction allows you to get a very high hold on it compared to most pocket pistols. The web of your hand winds up just under the slide - it might not work well for someone with a beefy hand. Regardless, the low bore axis reduces muzzle flip which is always good.
Unfortunately there's no slide lock, but I think that was a tradeoff they made to get it so thin.
I also like the Kel-Tec PF-9, and the Kel-Tec P-32 is my anytime gun.