Good question!
I have the same problem. I found out that the black filament that was handed out during the latest workshop @ protospace was ABS. The white is not. I also have some red and pink. I don't know what that is yet. Siert showed us a trick: burn the plastic with a lighter and smell the fumes... but I forgot how each should smell.
I've seen screenshots of Netfabb that has ABS and PLA templates that you can use when you create a new material. That is probably an extra feature of Netfabb pro?