Typically reseller BFG manufactor overclocked cards that come with a lifetime warranty..
I was looking at the BFG nVidia FX6800 GT they had for offer at $399, it was very good value. Basically it ran at the performance of the Ultra due to the overclocking, but about $150-250 cheaper. The only downside is that it was 128MB... I forgot the website, but punch that into Google searching under Australia and you'll find some good ones.
ASUS are also very good manufacturers.. not necessarily for the budget conscious though.
The ASUS nVidia Geforce V9999 6800 is priced at $345... it's the best priced card you'll come across, especially considering the performance it packs. It doesn't have the bells and whistles of the GT, LE or Ultra and is only 12 pipelines.. however for a budget performance card, this is your next best choice.
I try wherever possible to avoid ATI - I prefer nVidia just like I prefer AMD over Intel.