You might as well get 8.1. You do have the option to downgrade your license to 7 if you prefer. However; Microsoft is bringing back the look and feel of 7 in the next 8.1 update so really, you might as well just go with 8.1
Downgrade license info
http://www.microsoft.com/oem/en/lice...id=AgeLxcT1jm4
I run a PC shop and I am recommending the same to my clients
a) if your upgrading an XP based computer that is still good enough (dual core ddr2/3) Then go with 7
b) new purchases...Win 8.1
http://techcrunch.com/2014/04/02/mic...n-windows-8-1/