When looking at the SP I decided upon the 64GB model because I can't imagine using 128 GB space. I moved the recovery partition to my SDCard as well as creating libraries there for all of my pictures, music and videos. I've installed Office Professional, Photoshop 64 and 32-bit, Flash Professional and Microsoft Expression as well as lots of other miscellaneous software. I still have 28 GB of space left. I run any games, Modern Warfare, etc... (for the little I actually game on this) from a usb 3.0 external hard drive that works remarkably well. I don't play Modern UI games - they seem silly to me. In addition to the software I have database files, Word docs, Excel, etc all stored on the SSD. So anyway, unless you have vast music, picture or video libraries that for some reason you don't want to put on an SDCard and you aren't loading up on tons of Modern UI games, you should be fine with 64 GB.