Buy the FX 6300. It is definately the best of the 3 CPUs. Here is a solid motherboard for your 6300 for only $70.
As far as a case, I personally don't like either. I would go for something like a Corsair 200r
, but its a matter of personal preference.
Hope I helped. Let me know if you have any questions. Cheers:)EDIT: The NZXT Source 210 and 220 are also nice cases for $35 and $50 respectively.