My first recommendation is to stay far away from the EOL AM3 platform (production of all AM3 chips has ended) and get an AM3+ board instead. This will support AM3 and AM3+ chips so 2 years down the road when you replace your AM3 CPU you will be able to use the same motherboard instead of having to purchase again.. I admit some AM3 boards will accept AM3+ but its better to just get the AM3+ in the first place.
if you don't plan on going with crossfire but want a good board that can overclock check out the AM3+ gigabyte 970A-D3. its 90 bucks and a damn good board for overclocking and will support piledriver when it comes out otherwise if you can get your hands on the board the above guy suggested get it, its a very good board for that price. only downside to the crosshair IV is its not am3+ which means there is no longer any new processors being released for it.
I stand behind the Asus RoG and TUF series - grab a ROG Crosshair V if you can find it inexpensively or a TUF Sabretooth 990FX. AM3+ is the way to go as others have said. The Sabertooth should definitely be in your price range, if you're a little flexible. Asus also has "unnamed" 990FX boards as well, which are less expensive but still solid.