A lot of those degrees interrelate with each other - jobs wise. So say you did Comp Eng, you would still be able to get employed doing normal IT Sys Admin or Developer related jobs (Just bear in mind an IT degree is usually shorter than an Engineering one, i.e. 3-4 years (IT) versus 4-5 years (Eng) full-time). Comp Eng specifically, leads to more job demand overseas. Australia doesn't manufacture or design any chips. We offer plenty of IT Services though (and some niche software products/services), such as IT Support, Telecommunications, Web Hosting, Software Consultation/Development, Sales (importing tech products from overseas), and we have small pockets of indie game devs here and there, (with rare big names like 2K Games Australia in Canberra - most Game Devs shut-down since it's very hard to create revenue here in Aussie land, without the cashflow to spend on worldwide marketing and distribution - provided your team has a good enough of a game to sell).
Check here if you want accurate facts about jobs in Australia.
www.joboutlook.gov.au/
Also these may be a good site to read:
www.computing.unsw.edu.au/study-options/
www.computing.unsw.edu.au/study-options/degree-comparison.html
www.unsw.edu.au/sites/default/files/documents/2014 cuttoff list_ATAR_Alevel_IB_OP.pdf