My first car was a twin-cam AE92 Toyota Corolla hatchback. Was nice and light, wasn't super fast but decent enough to beat 'average' cars from the lights, and was in great condition and perfectly reliable. Pretty good economy too. Power and economy were noticeably better when I started using Shell V-Power petrol too. The only things I did to it (besides 10,000km services) were add a MP3/WMA CD player and window tinting. The aircon worked great, but back when we had those hot summers the tinting helped a lot (darkest legal from Tint Professor). I remember driving from Melton to the city on Black Saturday with the a/c on and I was freezing inside (48 degrees C outside). Insurance was cheep too (roughly $400 comprehensive for age 18.
So something Japanese (preferably Toyota for reliability) that's been looked after is probably your safest bet.