For those who choose a laptop as their primary computer, storage space is an eternal problem. Between games, music, movies and pictures, the gigabytes can disappear before you know it. While this is true of any PC, notebooks have it doubly rough: they usually only have space for one drive, and that one has to fit the 2.5 inch form factor. Today, we'll be looking at one of Seagate's answers to this challenge, the Momentus 640GB.