Unfortunately I've never travelled abroad so.... not counting Griffith + Leeton local grounds (outside of NPL), but unfortunately also counting other sports...

Solar Mad Stadium (Griffith NSW - NPL)
Greenway (Tuggeranong ACT - NPL)
Gungahlin (Gungahlin ACT - NPL)
Deakin Stadium (Deakin ACT - NPL)
Riverside Stadium (Queanbeyan NSW - NPL)
O'Connor (O'Connor ACT - NPL)
McKellar Park (Belconnen ACT - NPL & ALW)
Bruce Stadium (Belconnen ACT - ALM, ALW, AFC Asian Cup & Socceroos)
AAMI Park (Melbourne VIC) - ALM & NRL
Melbourne Cricket Ground (Melbourne VIC) - AFL & WWE
Stadium Australia (Sydney NSW) - NRL & Socceroos
Central Coast Stadium (Gosford NSW) - NRL
Parramatta Stadium - pre-renovation (Sydney NSW) - NRL

Within Australia, the two I really want to do that I haven't (because who knows if/when I'll get to travel) are Suncorp (maybe the Olympics is my chance to go there for packed out football?) and Lakeside in Melbourne.