HDD: the samsung Spinpoint f3 500gb should be around that same price (I'm guessing this is $CAD? Much better performance than the cav greens and even the cav blacks in some categories.
PSU: please link in some info on this. Scythe is said to use Topower as their OEM and they aren't one of the better ones out there.
Ram: Seems high depending on where your from. Anything more Cas 7 1333 won't provide any better performance, so don't pay for more than that. If you do get 1600, cas 8 or 9 can be lowered to 1333 and tighten the cas down to 8 or 7 (lower is better)
CPU i5 750 is best bang for buck CPU out right now, good choice
DVD - seems expensive for US, but I don't think you're ordering from the states.
Even though there's a spot for another fan on the top, I very much doubt you'll be running into any cooling problems with the included fans. Save the money and leave that top slot open.
The GPU question can't be answered without knowing what resolution monitor you have and if you plan to upgrade. If you're on a 1280x1024 monitor, I'd save the money. If you're on 1680x1050 or larger, you'll get some performance out of a 5770, but since you have a GPU now, might be worth waiting till Nvidia comes out with Fermi and see if ATI counters with some price drops. Maybe the 5850 will come into budget in 6 months or something. Only time will tell on that one.
thanks for the input, i will be ordering from australia, shopping from www.pccasegear.com and www,msy.com.au, they are the cheapest prices i can basically find in the state. my monitor resolution atm is 1440x900 though could possibly be running a 1920 x 1080 @ 60 Hz. 1600 ram is only $5 more then the 1333 so thats a no brainer. Could also get APEVIA 600W Dark Side Power Supply for $95, is this a quality brand/product, and is it enough juice for what the PC needs?