Roommate's dad carries a .40 226 for his LE job, and loves it to death.
For me, if it was a duty weapon, and I had the option, I would NOT pick a striker-fired weapon; I like the ability to hit the round again. That being said, within the "striker" weapons, the XD could be nifty depending on which setup, I've heard WAY too many stories of .40 Glock KBs, and the S&W 9mm I've had some trigger time behind was pretty nice; I"d probably go with the S&W.
But my first choice would be the 226.