I think the best thing about wine is everyone has their own opinion. Some think a $5 bottle is fantastic and sometimes they are but not often, I like the little wineries around McLaren Vale, they are close to us and you can spend some time talk to the staff or the wine maker, try some stuff and buy some pretty good wine for $10-$30 a bottle cheaper for a case.
The $30+ is getting a bit expensive for us an we don't buy much, but the difference to me between a good shiraz around $25 compared to a good shiraz around $40 just isn't worth it.
Half the fun is buying it and the other half is cooking a bbq and drinking it with mates.
I figure there is no danger of me becoming alcoholic if its not toooo good. Keeps my consumption well moderated.
The other day I poured some Solo Lemon softdrink into half a glass of red just to see what it would taste like. NEVER EVER do that; it was the absolute worst taste I have ever come across.