Consider buying from John Lewis. The price will be the same as everywhere else, but you get a 2 year warranty as opposed to the standard 1 year offered by Apple.
... I bought my son a MacPro (?) lappie a couple of months ago, got the student discount and they were doing good deals on printers (i.e. free) and 3 year warranty reduced to £50. Interestingly they offered the same price in store as on the net.
Don't know about architecture, but there are several industries where Macs have long been traditionally used. Video editing, sound recording and graphic arts for example.
It may be a concious choice to teach students on the sort of equipment that they are likely to encounter in industry.
Also Macs are, and always have been, far superior [size=-2](he typed on his pc )[/size]