I hear you...my 4th M&P will be here tomorrow. I have a 5" 9mm Pro, a .40 FS, and a .45c. I ordered another 5" Pro for a spare since Bud's had a good deal on them.
Yep, I started with a Plain Black S&W M&P 9C with Manual Safety. Then to be politically correct and fully intergrated I got a S&M M&P 45fs that is Dark Earth with Manual Safety.
I have done the Burwell modification to the sear in both of them and they are trully sweet shooting guns.
Yup its gotten to me also. Started with the M&P 22 and then the M&P 15-22 and then tonight I got a M&P 9c. My LGS said he has some new M&P 15 sports coming in and he'll give me a volume discount on it. LOL