Open Question: what do you think of this computer build?

hey, i had a similar post to this before but now the specs have been updated so what do you guys think of this: its all in australian currency (aud) CPU: Intel Core i7-930 - $349 HardDrive: WD SATA 1TB - $77 DVD Drive: SATA Sony - $30 Motherboard: Asus P6X58D-E - $275 Graphics Card: 1G GTX460 Gigabyte - $275 RAM: 6G Kit ddr3 2000 G.Skill-Trident - $239 Monitor: 23” 5ms DVI Acer G235HBMD - $194 PSU: Thermaltake EVO Blue Gaming 650W - $147 Case: Thermaltake V9 - $99 OS: Windows 7 Home Premium 64-bit - $110 Wireless: PCI-E TP-Link WN781ND - $25 Headset: Plantronics 367 - $38 Build Fee: $70 TOTAL: $1928 and would 1600mhz ram be enough or would the extra speed REALLY help.. because it would help if i could go with the slower speed as the price would make it just under budget oh and im helpless at putting it together so scrapping the $70 assembly fee isnt really an option one more thing, will having a separate hard drive just for the os make much of a difference in terms of speed. iv researched it a bit but there were mixed answers. thanks :)