The Windows 10 preview is here; at least in a really early form. From the images I have seen it looks like a combination of Tiles from Windows 8 and program selection from Windows 7. At least, that is how it looks in the current version. Follow this link http://blogs.windows.com/bloggingwindows/2014/09/30/announcing-windows-10/ to get more information.
Windows 10 is far from complete. If you want to participate in the community preview Microsoft makes the current version available. Remember now that this is a very early product, and that the way things look are likely to change. Perhaps those changes may be based on your input if you participate in the program.
Participating is not for the faint of heart. You need to know how to work with ISO images, and be able to install the operating system from scratch. Also, you should plan on losing work each time you update to the latest image. It may not happen, but, you have been warned that it can. They also disclose that there may be bugs in the software causing it to crash or do un-expected things.
But, if you want to play with the latest/greatest, this is your opportunity. You should be able to influence the final product. You can go to http://insider.windows.com/ to take a look at the program. You will need a Windows Live or similar login to participate with the program.
Cheers,
Ben