Look, honestly, many people aren't going to enjoy tax law. It can be tricky and complicated, there's some maths involved (not very complicated maths thankfully) and it's just generally quite dry - you'll learn a bunch of rules on how to calculate income tax, GST, capital allowances and so on. It's handy knowledge to have if you're doing commerce/law I think, or wanting to supplement your knowledge if you intend on pursuing careers in accounting/finance or tax law.
If you're interested more in the policy issues behind taxation, this is a newly introduced subject that looks interesting and is taught by a highly competent person:
http://www.monash.edu.au/pubs/2013handbooks/units/LAW4243.htmledit: I've now taken this subject and written a review on it hereStephen is very good. The only criticism I have is that he wrote all the prescribed books and every single lecture he will talk about how brilliant the books are because he wrote them, hah.