I still prefer the 650Mb CDs. I have been burning all the Mandrakes since 8.0 (and skipping 9.0) to the same set 650Mb CDRWs. If you stick with 650Mb it makes it one less thing that can go wrong when someone asks to try it.
Whatever you do, please don't create two differing sets of CD sizes (i.e. if you go with 700 don't also make a 650 version). This becomes a maintenance nightmare as people will mix up CDs etc.
