And unless Oxford has a significantly higher proportion of white-tie events than Cambridge, I'd doubt you'd need one at all, and would hire for any occasions you did need it. A dinner suit might be more use though.
I'm coming up to my second year and so I like to think of myself as knowledgeable on this subject.
Subfusc is used for matriculation and prelims only.
You will need a dinner suit depending on how many balls you plan on going to, there are loads of college balls in trinity and there are a few in hilary and michaelmas so I'd say its worth just buying it all yourself.
So (for men, evidently), Sub Fusc simply requires a simple dinner jacket and a white bow tie? Must we use the shirts with the funny collars (sorry, from Yorkshire) or will any plain white shirt do?
Any plain white shirt will do and no you won't need a tail coat unless you plan on going to a lot of white tie events or conducting an orchestra any time soon...
So (for men, evidently), Sub Fusc simply requires a simple dinner jacket and a white bow tie? Must we use the shirts with the funny collars (sorry, from Yorkshire) or will any plain white shirt do?
Sub-fusc for men includes a dark suit (NOT a dinner jacket) and a normal shirt with collar, not one of the things you wear with a dinner jacket with the funny collars. You'd get away with wearing a dinner jacket (probably) to matriculation, but you might feel abit silly. Better to get a normal suit.
Bringing a dinner jacket is a good idea, since there will be the occasionaly black-tie do (the only ones I've been to were eights dinner and our college ball), but alot of events will say 'smart' on the dress code, so a normal suit would be best for them too.
This is the sort of thing you should be thinking along the lines of.
As far as I know, your shirt can have either the wing or the 'normal' collar. Lots of people have the wing collar (as you have to wear a bow tie, and wing collars are meant to be worn with bow ties), but lots have the normal one (as it is not a dinner jacket you're wearing, you're not meant to have a wing collar). I think it's roughly an even split between the two, so get whichever you want.