I had an eBay seller openly violate eBay TOS and make me cover the additional PP fees and eBay fees incurred on his sale via inflated shipping costs.
I brought it up with him and his simple response was "I sell items on eBay and it is my livelihood. I do not sell for charity. If you don't...
Go big or go home. That you're even asking yourself, OP, says enough.
I was lucky to find myself in the position of whether or not I should add a second 580 to mine to SLI.
I did, and haven't looked back. Waste of money? Perhaps, but I was ready to spend it anyway.
Crucial M4. With the new 009 firmware update that was released, increasing speeds dramatically, and no freezing / instability issues to boot (SandForce i'm looking at you), it's pretty much the go to for an SSD these days.
Not to mention it has constantly a ton of sales.
My 4870x2 is still chugging along quite nicely at 833/915, so a 5870 would be more than enough considering it outperforms the 4870x2 somewhat.
And while many people will cite VRAM has some kind of huge issue, I find I hit my acceptable-playable-FPS wall at 1680x1050 in a game like GTA IV...
I don't think that many e-tailers are selling many P67 boards at all, let alone the very limited number of mATX boards (I think at the moment there is only the Asus?)
Unless you can get one of those line graphs that plots fps over time. The hitch will almost certainly bring a downward spike.
Also, OP, microstuttering benchmark charts for you might be useful.