G'day,
This kind of thread comes up pretty regularly, and if you use the search function you'll get plenty of opinions.
For all those who'll say to do an aviation degree, there will be an equal number who say to do an accountancy or business degree, IT, etc, as a backup in case you lose your medical.
A Bachelor degree is three years of full-time study (longer if part-time) and the last year is reasonably intense. Plus HECS, etc, makes it a considerable investment in yourself.
Similar, in fact, to the investment you make in yourself if you go for your CPL/MECIR.
DIVOSH top tip: DO NOT DO A DEGREE AS A BACKUP!
Only do a degree if you really want to do one, and do it to gain a qualification in a field in which you want to work.
Besides, most degrees/skills have a shelf-life.
I completed my BSc in 1986 and I majored in Genetics, Biochemistry, with a sub-major in Immunology. Oddly enough, I found myself working in IT in 1998, and I had a reasonably successful I.T. career until I finally left I.T. in the beginning of 2006.
If I lost my medical tomorrow, there is no way I'd get a job in Biology. I'd probably get another I.T. job, but in around 2 or 3 years that wouldn't be available either, as those professions have moved on, and my skill-set would be obsolete.
If you want to have an aviation career, my advice is to fly. Do the degree part-time later on.
DIVOSH!