If you are looking for something to download then why not download the Windows 8 Developer Preview and have a taste of the next desktop OS from Microsoft. Keep in mind this is a pre-beta which means you should expect bug and instability.
Recommended hardware is similar to what you should already using with either Vista or Windows 7:
- 1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
- 1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit)
- 16 GB available hard disk space (32-bit) or 20 GB (64-bit)
- DirectX 9 graphics device with WDDM 1.0 or higher driver
- Taking advantage of touch input requires a screen that supports multi-touch
Use the following links to download the version you find adequate:
Windows Developer Preview with developer tools English, 64-bit (x64) 4.8GB
SHA-1 Hash: 6FE9352FB59F6D0789AF35D1001BD4E4E81E42AF
Windows Developer Preview with developer tools English, 64-bit (x64) 3.6GB
Sha 1 hash – 6FE9352FB59F6D0789AF35D1001BD4E4E81E42AF
Windows Developer Preview English, 32-bit (x86) 2.8GB
SHA-1 Hash: 4E0698BBABE01ED27582C9FC16AD21C4422913CC
Don’t forget to watch the Microsoft preview of Windows Server 8 @ 9am Pacific time, Sept. 14.