Sapphire 4870 to Sparkle gtx 470... worth the upgrade?

Hi,

I've been running off of my 4870 a while, and was interested in working my way into 3d gaming eventually. I originally planned on getting a 6870, but after finding out that monitors weren't readily available, I looked to Nvidia. 480s still seem expensive to me, so I went down a notch to the still-impressive 470s. There's a Sparkle on sale for $250, but wasn't sure if I'd be getting that much more performance for the money. Again, I plan on getting into 3d gaming EVENTUALLY. This would just be the first step, as I don't have a proper monitor nor the Nvidia glasses yet. Any pros/cons to the upgrade are greatly appreciaited. I've also heard that the Nvidias tend to suck more power than the AMDs, and I was curious what people would suggest as a PSU. Also, my mobo pick was dependned on me getting an AMD graphics card. I tend to favor Asus mobos(just preference from my experience with them). Are there any equivalent mobos that would support an AMD processor and Nvidia graphics card?

My current build:

Windows 7 Pro 64-bit
MSI 880gma mobo
AMD 1055T hex-core(not o/ced)
1x 1TB HDD Sata300
1x 320GB HDD Sata300
1x Dvd-r/w
1x Sapphire 4870(standard I guess)
2 Gbs of DDR3 1333 Ram

I plan my future build as being:

Windows 7 Pro 64-bit
Asus Crosshair IV <------------------------------------------Good for Crossfire but what Asus board has the same performance but designed for SLi?
AMD 1055T hex-core(not o/ced)
1x 1TB HDD Sata600
1x 1TB HDD Sata300
1x Dvd-r/w
GPU????<----------------------------------------------------Main issue
2 Gbs of DDR3 2000 Ram

*Edit:
Forgot to mention. It doesn't have to be Asus. I just prefer that if someone knows of a compatible board. Also, I was hoping to get a board with sata600 and usb3.0 capabilities.

motherboards can support any card and some motherboards can support crossfire and sli. so don't worry about that.
we'll find one of those.
think about adding a SSD this time and not two bigger HDD's.
also 4GB's of RAM and if not overclocked then not need for 2000MHz, 1600MHz will be sufficient.
AMD by defaults runs 1333MHz like you already have, you can just get a matching set and run 4GB of those.
nVidia is slightly more power hungry than ATi but better in overall quality and per performance.
I do not recommend the Sparkle brand .!! No.
I suggest you look for another GTX 470 on sale or even just SLI 2- GTX460's.
Corsair, XFX, Rosewill and Antec are some good power supply manufacturers.

if need of HDD then look at the Samsung Spinpoint F3 models
stay with dual channel RAM even if 6GB, it would look like this:
6GB = 4GB(2x2GB) in slots 1 and 2 + 2GB(2x1GB) in slots 3 and 4.
both sets of RAM has to be matching sets.
Sparkle is of cheaper quality, look for another manufacturer on sale.
if not a multi-set up of GTX460's the GTX470 is cool alternative, i like the nVidia from ATi move.
you can get it for a decent price.

Thanks for the quick replies. I'm gonna glance over these boards and report back if I make a decision.

The ATI 4870 is equivalent to the GTX 260 Core 216.

2 x GTX 260's in SLI are equivalent to the GTX 470. I know, I used to have 260's in SLI, and put in a GTX 470 myself. Benchmarks are basically the same.

So, that being said, the GTX 470 as a single card upgrade from a single ATI 4870 is a good jump in performance.

As for Power Supplies, the Corsair stuff would be my preference over XFX. I just put a Corsair TX650 in my wife's system, and a Corsair 400W in my in-laws computer last night.