Windows 7 Professional. So I think if you want

Windows 7 Ultimate
Windows 7 Ultimate (Ultimate Edition) is the most flexible and powerful version of Windows 7. It is combined with significant easy to use characteristics on the Home Premium‘s entertainment functions and Professional business functions, and its features include the ability to run many Windows XP productivity programs in Windows 7 Mode. Because of the increased security, you can use BitLocker and BitLocker To Go to encrypt the data. Windows 7 Ultimate is the complete package and includes everything that Windows 7 has to offer. It includes additional security features such as Applocker and Bitlocker that makes your Windows 7 PC even more secure. Windows 7 Ultimate also includes a multi-language pack, allowing you to switch between 35 languages. All of this can be achieved by the Windows 7 Ultimate. Windows 7 Ultimate comes with the following set of features that distinguish it from other Windows 7 editions: BitLocker file encryption; Direct Access; Bruch Chcle. Now I will list some significant characters of Windows 7 Ultimate and hope you have knowledge of Windows 7 Ultimate.
(1) Getting Started
This replacement for Windows Vista's Welcome Center no longer appears the first time you boot into the Windows desktop, but it still provides a central location for discovering new features, personalizing the system, transferring data from your previous Windows PC, and discovering and launching other common tasks.
(2) Bitlocker To Go
The full-drive encryption feature that first debuted in Windows Vista has been updated in Windows 7 to support removable USB storage devices like flash memory drives and portable hard drives.
(3)DirectAccess
This feature is aimed at business users who need to securely access corporate network resources while away from the office. Essentially a simple replacement for VPN connections, DirectAccess requires Windows Server 2008 R2 on the server-side.
(4)Blu-Ray support
Windows 7 natively supports Blu-Ray optical discs and enables you to write to Blu-Ray recordable media.
(5)HomeGroup
Microsoft has consolidated the most common network-based sharing tasks into a single simple interface called HomeGroup. Computers in a HomeGroup can easily share documents, digital media files, and printers over a home network.
The Windows 7 ultimate contained all the features of Windows 7 Home Premium and Windows 7 Professional. So I think if you want to a most full functional type, this version will be your best choice. In addition, you can save more money when you buy it.