PSU advice please.. and a bit of general advice too!

[Atomik]

Hi.

I'm gutting my existing rig and chucking a new mobo, proc and gfx card in there. The evil hybrid will look something like this:

Abit AT8 ATI RD480
AMD Athlon 64 X2 Dual Core 3800+
ATI Radeon X1800 XT 512MB
2 X 80 GIG SATA HDs in RAID0 array
2 X Optical Drive
2 X 512 DDR400

Also, I'd be aiming to add a second GFX card in there in the future to run in crossfire mode.

Will I need a new PSU initially? If so, what's my best buy? How much power do I need? I heard rumour there's some issue with crossfire and single-rail PSUs?

Any general opinions on the above rig? Anything that I'll need to upgrade that I've missed?

Cheers.

 

[Atomik]

I'm running a Thermaltake 480W, but it's pre-PCI-E. Yeah, I'll be upping the RAM by another gig - just need to bring the upgrade in on a budget at the mo.

 

[Atomik]

So will I need a new PSU? Anyone? And how much power?