Memory

The 64GB version is nowhere near big enough if you plan on using the Surface as a laptop replacement (although it might be ok for use as a tablet).  Part of the reason 64GB is not enough, is that you lose more than 30 GB of that just on the OS.  You can gain back around 6-7GB by moving the restore partition to USB but even so, that doesn't leave you with much room.  I recommend going for the 128GB version of the Surface Pro, plus as much additional memory as possible in the form of an SDXC card.  I've got the largest possible SDXC card (currently 64GB), which gives you a total of around 164GB of usable space (although I'm not sure if the SDXC card will have speed issues and whether you can install applications to it - I'm planning on just using it for data).  If you need more storage space then grab a 1 or 2 TB external drive, such as the seagate passport or similar (usb 3, powered off the port and portable so you can easily take it with you).

 

I currently have all the apps installed that I use on a day to day basis (including Office and Matlab which both take up a bit of space).  I've still got over 50 GB free on the internal memory but 10GB of that will disappear when I bring the rest of my data over from my laptop.