EVGA X58 Micro vs SLI LE

Well, considring that you want to CrossFireX and add a soundcard later, I'd go for the EVGA X58 SLI LE. The EVGA X58 SLI LE offers five PCI-e slots, four 16x, although only one is running at 16x, two are running at 8x and one is running at 4x. There is also one PCI slots as well, IIRC. There is one PCI-e 1x slot, although it is blocked if you use a dual-slot graphics card.

The Micro only has two PCI-e lanes, although both are at full 16x. The 8x bandwidth on the X58 SLI LE won't bottleneck any graphic cards except the HD 4870X2, HD 5970 and GTX 295, and dual-gpu cards of that sort.

So, with two way CFX, you would still have two PCI-e 16x slots available, one at 4x, the other at 8x, and these could be used for a PCI-e 1x sound card, whereas with the Micro, there wouldn't be any expansion slots left.

Just to note that the X58 SLI LE can do three way SLI + PhysX, but to take advantage of that you need a case with 8 expansion slots, like the Raven RV02, and also a single slot PhysX card like a 9500GT and single-slot versions of 9800GTs.