Windows 8 is a lot better. Great for multitasking. It's basically Windows 7 improved. You don't need to use any apps or use the start menu. Everything is on the desktop already.
Microsoft isn't going backwards. Windows 8 is going to be on tablets and phones.
They're already coming out with a tablet-pc that runs Windows 8. It works exactly like a PC would. With the new SkyDrive feature, you can share files between your tablet and PC within seconds.
You can transfer Minecraft to that tablet and play touchscreen Minecraft. You can upload your worlds and other folders/mods to that tablet and play on it there also.
If your looking for Windows 9 to look and feel like Windows 7, your going to be disappointed. Like I said, Microsoft isn't going backwards. Microsoft will probably design Windows 9 to function 'in the cloud.' All of your data will be available in servers around the world. Even though this is very unique and cool, hackers will find ways to make it a unpleasant for all of us, but that's a different story. Microsoft is not making another Windows 7. End of story.
