Hi Carley and welcome to the forum!
First off, normally its best to post links to the bikes you are talking about so each individual forum member does not have to google all the bikes in order to help you out. Just a tip, you will get more responses that way.
Second, there are ways to put a rack on just about any bike, almost. However, most bikes that do not come with typical mounting points for a standard rack are probably not going to be well suited to carrying a load.
Congradulations on the decision to join the car-free ranks! We all applaud you! Depending on what the public transportation is like, and where you live it maybe likely that about one a week you will have a pretty big load on the bike for stuff like groceries, laundry, or even home improvement stuff. Having one bike that can do all those things is a major plus. I am assuming you already have a fun and fast fixie for when you don't want to ride the heavier bike right?
There are lots of bikes out there that meet the criteria of having integrated shifters and are able to carry a rear rack properly. I know many of us car-free people are using touring bikes with this sort of set-up.
The motobecane looks like it will take a rear rack but not fenders. Does it rain where you live and do you ride in it?
Link:
http://www.bikesdirect.com/products/...agesport_x.htm
Ditto for the Raleigh, can take a rack but maybe not fenders.
link:
http://www.raleighusa.com/bikes/road/revenio-10-11/
Ditto again for the Trek
link:
http://www.trekbikes.com/us/en/bikes/road/1_series/11/
If you are looking for something that might be able to take wider tires, handle a load better, and also have fenders consider these the Novara Rondonee or Windsor Tourist.
http://www.bikesdirect.com/products/windsor/tourist.htm
http://www.rei.com/product/744804