Windows: If you're installing Solid-State Drive (SSD), you probably won't be able to migrate your entire drive over, since SSDs tend to be smaller. Migrate OS to SSD will let you specify which folders you want to migrate to the smaller drive.
We've shown you how to upgrade from a small drive to a spacious one, but SSD users have the opposite problem: Not all of their data can usually fit on their new, smaller drive. Luckily, you don't really need your documents and other data on the SSD — just the OS and program files. Migrate OS to SSD is a program that will let you select which folders to move over to the new drive, making the migration progress quick and simple.
Just fire up the program, choose your target disk (the SSD), and deselect the folders you want to keep off the drive. Generally, you can just untick the Users folder, since that's where most of your space-eating data is stored. The program will move just that data over, leaving the first drive as-is for you to clean up later (you know, after you're done ogling over the blazing speed of your brand new SSD).
Paragon Migrate OS to SSD is a free download while in the testing phases and is available for Windows only.