According to the US Military, the two most reliable pistols are the Beretta 92 and the Sig P226. I shoot better with the Sig. If you like the 1911, and the feel of a quality steel gun in your hand, the Glock, although a very reliable pistol, might not be your first choice. When I did my Black Badge, one guy on my course had a Glock that kept jamming, I've heard they have a problem with limp wristing.
My hand down favourite are the Sigs. If you want a slightly smaller gun, try the Sig P229. It is used by OPP, Secret Service, NCIS, FBI, the list goes on but we can't forget Jack Bauer
It is incredibly accurate and incredibly reliable.
http://www.sigsauer.com/Products/ShowCatalogProductDetails.aspx?categoryid=8&productid=63
If you have a smaller hand, there is the SIG P226 E2 (Enhanced Ergonomics).
Also keep in mind .45 ammo is a lot more expensive than 9mm or .40 cal. If you intend on shooting competitively I'd recommend 9mm.