What about splitting the difference with .40 ?
The .40 S&W isn't much of an improvement over the 9 MM. Especially today with all of the modern, reliable expanding, high performance self defense ammo that's available out there. It's basically nothing more than a shortened 10 MM, which is a hell of a cartridge. Even a lot of the police departments that bought into the .40 hype in the late 90's, are now going back to the 9 MM.
About all it does do, is give you more recoil, less capacity, and tear up guns faster. It's not that it's "bad". It just doesn't offer much, if any improvement. It has become the proverbial solution to a non existent problem. The ammo is more expensive, albeit not enough to make much of a difference. And during all of the seemingly never ending ammo scares we've been through in the last 7 years, it's been a bit more available. But now with 9 MM Ball dropping back to around $10.00 a box, and pretty much available everywhere, even that incentive is gone.