I originally was going to go with an MSI FM2-A75MA-E35 (http://pcpartpicker.com/part/msi-motherboard-fm2a75mae35), but this motherboard came out recently (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130741), and it seems to be a slight upgrade to my original plan. I already have the A75MA bought, but I kind of like the fact that with the A78MA I could upgrade to a better cpu later, while I couldn't do that with the A75MA because it supports FM2 cpu's (Not FM2+ like the A78MA). Is it worth it to go through the hastle of returning the A75MA?
(It's for this build: http://pcpartpicker.com/user/OceanMonkeys/saved/3bbM)
No. Don't upgrade your motherboard until you can afford something decent.
I'm building a budget ($600) gaming pc. I haven't built the pc yet, I'm buying parts.
You can get away with the stock cooler on that processor; no need for the gigantic 212 EVO unless you plan on some serious overclocking. (Even with the FX 6300 that I mentioned).
I would advise 2x4GB memory instead of one stick. It has better bandwidth.
Upgrade that 7870 Ghz to the 270x with the money you save not using the 212 EVO.
If your budget can stretch it a bit more, look into an FX 6300 and AM3+ motherboard.
You might want a regular ATX board instead of micro ATX for more features and plugs.
You may find you hit the limit of $600 with that.
Also, there are cheaper cases than the one you are getting that serve almost as much features that you probably won't need (like 6 hard drive bays instead of 8). I'd recommend the Corsair Carbide 200R. $20 cheaper and I have one and can recommend it. :D
Where's your PSU btw?
If you have a Micro-Center near you, http://www.microcenter.com/product/398237/GA-78LMT-USB3_Socket_AM3_mATX_760G_AMD_Motherboard plus the FX-6300 runs you $89.99. The CPU is on sale and with a bundle sale, you're basically just paying for the CPU and getting the Board for free.
The bundles themselves: http://www.microcenter.com/site/products/amd_bundles.asp
Holy cow, that's some good prices.