You don't really describe what you need in terms of performance, drive space, what application you will be using, etc. For us IT folk information like that is required to really make a recommendation on things like that.
As long as you don't need to load tons of movies, pictures and song which will fill up the drive space you can get a smaller HDD/SSD.
I work with laptops, desktops, servers, VMWare, NAS/SAN arrays all day long for the past 15+ years so I believe that gives me the right to have a solid opinion of a quality machine. All of these machines I work with are generally Windows based, but for my home life I have converted over to Apple products and would never go back at all. Quality and design beyond compare.
For what you say you need I would recommend an Apple MacBook Air 11". For $1350 you can get a machine with max i7 CPU (that means more L3 cache than the i5 CPUs), 8GB RAM and 256GB SSD. If you need more disk you can go up to 512GB SSD for another $300.
You say you need Windows 8.1 and that is fine. Use Boot Camp to load Windows and you should be good to go.