Well I have both a G17 and a 1911, and .45 is the only way to go with a 1911.
1st let me say if funds are an issue the G17 will cost up to $10 less per box/50 rounds. Unless you choose the 9mm 1911, but I would encourage you to buy the Glock if you are intersted in 9mm, later you will want a .45 then get the 1911.
Secondly these are two completely different pistols, and really I don't think they can be compared against one another. I love both of them and could not choose one over the other except I shoot the Glock better.
I actually find the 1911 does not feel as comfortable in my hand. It is heavy, and I don't like the position of the safety. At the same time I like that it is all steel and feels very solid, unlike the G17. When you hand a Glock to a first timer you will see a look of almost dissapointment, just not the weight they expected, but the 1911 gets a smile everytime.
Now I will also say that you really do need to have both of these pistols in your safe eventually, so really it doesn't matter which you choose.
.45 acp is a great load because it is powerful, but not so snappy as a 9mm, and is more of a big push with a heavy 1911.
I think it is the best choice if you are thinking about starting to reload is the . Low pressure cases, and heavy steel guns just seem a little safer for a newbie.