Alright, I'm going to toss my hat in for the XD in .45 acp. I had the chance to shoot one at a range while blasting away with my shotgun this past weekend, and I'm impressed. How they squeezed 13 rounds into a grip that comfortable I'll never know, but even for my carnie-sized hands, it felt just right. Very controllable, and like Chuck said, it feels smoother than the 9mm (never fired the .40) while firing. Overall, the construction seemed pretty solid, and there was little wear & tear on it for a range rental. The Streamlight light/laser combo they had on the thing was kind of awkward, though, and I'm not sure if I would go that way.
I've got a friend out at the 46 FRS who has one, and he gave a pretty glowing review. He's pretty anal when it comes to his firearms, and especially so when it's one of his carry pistols. After he first got his XD, he took it to the range for some training, and after a full Saturday of shooting, he had this to say: "I TRIED to make it jam, but I couldn't. I even gave it to [A friend's fiancee] and she shot a 3in group." The lady in question is about 5'0", maybe 100lbs on a bad day, and has shot maybe 3 times in her life. I was there for one of those times, and it was not pretty.