It will probably be Windows 8 to ride on the success of 7. That said, it doesn't have the same ring, really. Maybe Windows X? Or maybe using an old code name, like Windows Vienna. I wouldn't really mind Vienna, it sounds nice.
If M$ keep to their tried and tested release path it'll be Windows turkey v3 Windows 98se Windows Turkey v1 AKA Millenium Xp Windows Turkey v2 AKA Vista Windows 7
Way to miss Windows 2000... More like: Windows 98se Windows 2000 Windows Turkey v1 AKA Millenium Windows XP Windows Vista (it really wasn't as bad as people say) Windows 7 Windows 8 ???