Honestly, it is not worth going all the way to uni for the ID card if you live far away.
Just go during O week IN THE MORNINGS where the line is really short (during the first hour of the day there's 4 photographers and no lines).
During mid day / afternoon the lines can be very long.
Oh also, you may need to get your name "corrected" at student services before you get your ID.
In short, it MUST be identical to the full name on your passport/drivers license/birth certificate. That includes middle name/foreign names. I never used my middle name in school, hence it was never passed on to UAC or UNSW for that matter.
This is a quick process. Just head to student central, opposite the main entrance to the library, fill in a form, then they photocopy the ID and change it for you in around half an hour. Do this before you go for your ID or you will get sent back and have to line up again.
For local students - you should also fill out the transport concession form and hand it in when getting your ID
Also, if you come more than one days, get it later on in the week when everything quietens down. First day is usually very busy, and by wednesday there is about half and very few by thursday/friday.