Microsoft today unveiled the various versions of Windows 7 that will be available when the new flagship desktop operating system launches. Here is a table of the versions an the features available in each:
Some versions like the Starter version (aimed primarily at the emerging netbook market) and the Home Basic edition seem to have very limited, niche application. The Home Premium version is the main edition for the consumer market, and the Enterprise edition is the main edition for large corporate enterprises. The Professional edition is roughly equivalent to the Vista Business edition and is targeted at small and medium businesses.
Unfortunately, Windows 7 Professional lacks many of the best features that SMB's will be interested in. It does include a few additional features that businesses can use that aren't found in the Home Premium version, like the ability to join a Domain, and additional data backup and encryption options. I think Microsoft misses the mark though for the SMB market. They are smaller than their corporate enterprise cousins, but they have essentially the same needs.
Many SMB's are in the healthcare or financial services industries and are impacted by mandates such as HIPAA, GLBA, or PCI DSS. They have a need to protect data on mobile devices and portable media and they really need BitLocker as much as their enterprise counterparts. SMB's like small banks or real estate offices have roaming users and multiple office sites and can benefit from new Windows 7 functions like DirectAccess and BranchCache.
Both DirectAccess and BranchCache require Windows Server 2008 as a backbone. That may explain why Microsoft, which targets SMB's with other server offerings such as Windows Small Business Server (SBS 2008) and Windows Essential Business Server (EBS 2008) may have left those features out of the Professional version. Admittedly, the SMB would have to have or be willing to implement the Windows Server 2008 infrastructure necessary, but my feeling is that small and medium business owners/users who want to gain all of the advantages of Windows 7 should just go straight to Windows 7 Ultimate.
For that matter, as an information security professional I have never really appreciated the Home version of any of the operating systems from Microsoft. In their effort to make them simple or dummy-proof they leave out key functionality and remove components that users need to secure and protect their PC's. Arguably, with no IT department protecting the network and no Help Desk available to clean malware infections and restore system functionality the home user market needs more security than the corporate enterprise market, not less. So, my recommendation for home users is to skip Home Premium and go straight for Windows 7 Ultimate as well.
Bottom line, I would probably narrow this down to only three options: Windows 7 Starter (because the netbook market will continue to grow as users seek out cheap portable computer systems), Windows 7 Ultimate, and Windows 7 Enterprise. If you aren't using a netbook, and you aren't part of a corporate enterprise, you should be using Windows 7 Ultimate.