well to start off, the athlon x4 750k is socket fm2, and the athlon 270 and 640 are socket am3. completely different sockets.
anyway, I bought this motherboard a while back, I had some old AMD parts laying around. This board accepts DDR2 and DDR3. and its compatible with old am2 cpu's and the newer fx cpu's. thats why i bought it, i wanted to be able to upgrade to the newest stuff. its a great little board. Its an ASRock N68C-GS FX. the only real drawback to this, is that you will be limited to 4 sata drives and only 8gb of ram.
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157309
here is this other asrock board. its newer its the ASRock 960GM/u3s3. it has usb3.0, six SATA ports, 2 sata III 6Gbps, it has support for 16GB of ddr3 ram, and it has a dvi port. its am3+ so it supporst am3 and the newer FX cpu's
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157323
inb4 someone says these are complete trash and tells you to get a gigabyte or asus board.