You should look into the i5-750. It's better in games, and usually a lot cheaper.
You're probably overpaying for that NZXT case. If you haven't already bought it, take a look at the Antec 300 Illusion. I'm not sure on AU amounts, so if that's drastically under the NZXT's cost, look at the Antec 900 and HAF 922. All of these are very good cases.
What's the CAS Latency on that RAM (also know as timing, it's a string of numbers)? You should be looking for some that are 7-7-7-x.
Ive actually now had to ditch the nzxt lexa s case because i was cant pay $150 for postage. Ive decided to go with the Lancool Dragonlord k62, its $152 AUD. Is this case better? Ill definatly take a look at that thread, thanks.
Not in gaming. Hyperthreading matters when using applications that heavily rely on the CPU and multiple cores.
In my opinion, the 860 is a waste of money. The choice is either the i5 or the i7-920. With the 920, you'll need a different motherboard and ram, which will typically add about $200 to the build (total with the CPU). You'll probably get more bang for you buck if you stick with the i5.