Get a 9mm. Because it's more popular, you'll have an easier time getting ammo for it. There's some question about the future of the 40. With modern ammo, a 124 grain 9mm +p JHP will do fine as a self-defense load. On the other hand, the market is flooded with used 40's right now.
Before you go to a store, look for a range that offers rental guns. You can try different ones out before you buy. There's really nothing worse than spending a lot of money and getting something you don't like to shoot.
Most of the guns you mentioned are available in 9 mm as well. In fact, the 40 was developed because you could (generally) fit it in a 9mm frame.
The guns you mentioned are all good quality, and priced accordingly. You might want to look at something more affordable like a Glock or Beretta. Still good quality. Do your research on the internet, several guns that "sound" American are actually made in other countries. "Rock Island," for example, is actually Armscor, a Phillipines company (with a good rep).
If you hang around these gun boards you will notice some never-ending fights over things like:
- Caliber
- Polymer vs. Metal frames
- Glocks vs. non-Glocks
- 1911s vs. everything else
Don't take it too seriously.