Building a computer for the first time :)

[JonSimonzi]

Also, was looking at other mobos and I'm not sure what to make of the PCI slots.

I know they are for gfx cards, some have 1,2, even 3. But It says

PCI Express 2.0 x16: 2 x PCIe 2.0 x16 (single at x16 or dual at x8/x8 mode) 1 x PCI Express 2.0 x16 slots (at x4 mode, 2.5GT/s)

Where as this Mobo just says it has 2 PCIe slots...Does that mean it runs both at 2.0 x16?

So if you have two they would both be running at half of what you run a single one for. I don't understand how that improves performance.

This isn't something I'm 100% sure about, so hopefully someone else will chime in and clarify. I don't think ANY 1156 motherboard has two PCIE x16 slots that will run at full x16 speed if using both of them. Like in that MSI motherboard you listed, the two blue slots are the two x16 slots. You can put one graphics card in either of them, and it will run at full x16 speed. Put two graphics cards in, the slots will only run at x8 each. Think of them as lanes on the highway, with 16 lanes max. As far as performance, I believe 5770s don't need full x16 lanes. If you were having a pair of 5970's in there, then you'd notice the difference in dual x16 slots.

As far as cases go, everything linked will fit all the hardware. Most modern cases can house a 120mm heatsink. I know nothing about the Rosewill Cruiser, but there are a few higher recommended cases. Antec 300 or 900, Cooler Master 690, or 690 II, HAF 922.