Unless you need any of this stuff: Backup and Restore Center Dynamic Disks Encrypting File System Location Aware Printing Presentation Mode Group Policy Offline Files and Folder redirection Windows Server domain joining Windows XP Mode Software Restriction Policies Or run 2 physical cpus, or need support for 192gb of ram instead of 16gb then Home Premium might be the better buy for you. Aside from that stuff, the major difference is the support time frames End of Support for home premium is dated January 13, 2015; 3 years' time End of Support for professional is dated January 14, 2020; 8 years' time That is all subject to change though, just like it did with XP, and judging from what we have seen of Windows 8, it might happen. Anyways home premium comes in 64 bit and would save you 35 bucks if you don't need any of the stuff above. I use home premium and haven't had a single issue, and I primarily use this pc for gaming and web browsing. Occasionally some video recording and editing, or photo editing. Though I didn't need any of the stuff above you might. Just throwing it out there.