Lots of knowledge here, good lord.
You'll meet many different people with different styles, but as a rule of thumb these guidelines might work.
Students: Jeans, T Shirts and Sneakers and you'll gel in well.
Lecturers probably a cord jacket and Jeans or something along these lines.
Formal is much more casual than americans might be accustomed to. Black or white tie is virtually never worn, except from higher diplomatic events. A dark grey or blue suit would do...