Need help with build mostly the video card

Well you should have heard about the new X3 720...I would suggest you look into that...
Its cheaper than the E8400, performs as good as the 8400 in games and better in most of the apps...
It is also a better upgrade path as the LGA 775 socket wont be here for long and intel plans to introduce new socket by this september...
Whereas AMD will be releasing new processors for the AM3 sockets...

X3 Phenom II 720 - $225 MSY
Gigabyte GA-MA790XT-UD4P - $277 Scorpion
4G Kit(2x2G) DDR3 1333 G.Skill NQ - $139 MSY
HDD: Seagate sata 500gb $86 MSY
CPU COOLER: Xigmatek Cpu Cooler D1283 $65 Scorpian Tech
Corsair CMPSU-650TXAU - $169.00 Scorpion
(Preferable 750TX $229 at scorpion - Can handle 2 4890 incase of future upgrade to xfire)
Case: Thermaltake V9 $111 MSY
XFX or HIS HD4890 $465 Scorpian tech

That looks like a good build but its about $137 over my budget.... so ill just go for DDR 2 and since the motherboard i chose is good enough then ill get that too so practically my build will be:

X3 Phenom II 720 - $225 MSY
Gigabyte MA790GP-DS4H - $209 MSY
HDD: Seagate sata 500gb $86 MSY
CPU COOLER: Xigmatek Cpu Cooler D1283 $65 Scorpian Tech
Corsair CMPSU-650TXAU - $169.00 Scorpion
(Preferable 750TX $229 at scorpion - Can handle 2 4890 incase of future upgrade to xfire)
Case: Thermaltake V9 $111 MSY
XFX or HIS HD4890 $465 Scorpian tech

Having trouble with the ram. Will 800mhz be fine for overclocking this cpu or should i get 1066mhz? And the cpu cooler will keep it reasonably cool if i overclock it to like 3.5ghz to 3.7ghz?

I guess i can spend a extra $43 bucks to get OCZ Tech SLI Ram 1066mhz. Is this good ram or should i get crucial or another brand?

Err im looking for a graphics card in 500 aussie bucks which is like 300 american or near that. 4890x2 is like 800 AUD lolz.

When converted thats only $347 wth? lol The computer store is like $465. Wierd aint it?

and plus the overclocking for the 4890 is just crazy. And i just found the motherboard gkay09 suggested for $199 and now im thinking of changing to that motherboard but does kingston make good ddr3 ram? or should i get Corsair? or G-Skill NQ?

Ok, thanks to everyone that has helped and guided me through. I have decided to go with gkay09 DDR3 motherboard since i found it for $199 and now i have my final list for my build and the build is:
(Australian Dollars)
Cpu: X3 Phenom II 720 - $225
Mobo: G-B MA790XT-UD4P- $199
RAM: Kingston 2gb DDR3 1333mhz- $52 (will upgrade to 4-6 gb in 2 months)
GPU: Sapphire 4890 1gb DDR5- $439
HDD: WD 320gb- $72
CPU Cooler: Xigmatek D1284 $45
PSU: Corsair 650wTX $169
Case: Thermaltake V9 $111
Total: 8 $1312
Changed to sapphire because its cheaper and it still overclocks well. Keeps it in my budget aswell of $1300-$1400. I still can accept changes if u see any flaws or change and parts just post it before Tuesday.

Since you're more worried about Crysis get a GTX275 as it's a little faster there than the 4890. There really is no point in getting the 285 with the 275 performing so close to it. Just overclock the GTX275 a little and it will pretty much be like having a 285 except in the few cases where the extra RAM in the 285 helps it pull ahead, slightly.