This is clearly going to be a defense gun, not a "fun" gun.
Anyone who knows a bit of recent gun industry history knows that the the S&W Sigma is a ****. Don't waste your money. Spend a bit more and get at least a Glock...or something that's been PROVEN.
Springfield Armory (not XD)
S&W (not Sigma, not M&P semi-auto)
Ruger (not LCP or SR9)
...and others...maybe Colt
In short...if it doesn't have at least a five to ten years of history, then it's new. New guns have bugs...as shown by Ruger's recall of the SR9.
Just don't buy cheap. That means no Rock Island Armory, Bersa, Taurus, Hi-Point, Jennings, and so forth. I know there are Taurus and Bersa fans out there, but those guns just aren't that durable. The keys to defense in terms of hardware is reliability and durability over long periods of time.
A Taurus may shoot well and be reliable, but probably won't stand up to serious training and the high round counts that go with it.
Additionally, buy from Virginia Arms if you're in NoVA (no I don't work there...but I have spent lots of money there). They guarantee everything that goes out their door...even a year down the road after purchase.
Don't be lured by price. Even so, there will be HUGE variances in pricing, even in NoVA. I've seen Glocks at VA Arms or Guns and Ammo Warehouse for $530ish priced in the $700 range at Blue Ridge Arsenal. Gilbert's has crazy prices too. Though you can get a Glock at a gun show for $479, you won't get any support...once sold, that's it.