M&Ps are ok, as are the Glocks, but unless you spend a little extra $$ you get more muzzle flip that you need to (depending on your budget). Also, with Glock, you have to be careful - there's .45 ACP and .45 GAP.
Or, you could go with a 1911 or a Sig P220 (again, depending on your budget). Both MAY be heavy, BUT, it depends on the person. I'm 5'9, 160lbs. I often carry my S&W 1911 (which is actually lighter than my glock 20, by a little). As far as capacity, it depends on your state. Some limit to 10 round mags (which is only 2 more than the Sig P220 - you CAN get 10 round mags for the 1911, depending on the model).
HKs are nice, too.
However, the real question to ask is why specifically a .45?
Insert witty comment here......
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