9mm suggestions
The only single stack 9mm I have shot enough to develop confidence in is the H&K P7 (M8 or PSP, you pick....) It has been uber-reliable, VERY concealable, it is my preferred primary weapon on hot days where strapping on my Para CCW in .45 is just too much.
For double stack pleasure, Glock's 17 or 19 are very solid choices for carry and competition. Tons of accessories/parts/upgrades you can do as you want, but really don't need them as far as I'm concerned.
Just to make sure I don't "diss" the S&W folks, the ONLY M&P worth owning for competition is the M&P 9 Pro. Has a reasonable DA trigger, nice fiber optic front post and a sight radius long enough to have it perform acceptably at longer range shots. All the stuff that makes it good for competition will make it a challenge to carry if you are smaller framed.
I've played around with the Kel-Tec's and just about every other small/cheap option. They'll work fine, but just couldn't make myself confident when carrying them.
For a solid, all-around piece, I strongly suggest you look at and try the H&K before diving into anything new and "sexy"...
Good luck on your search!
PS Why not just buy one of all of them and carry what you feel like each day?????