Also, it's often possible to physicaly transfert the disk drive from the old computer to the new one.
While transfecing things like your address book, internet favorites and your various settings and personalisation is quick, transfering the whole content of My Documents, My Music and similars, can take several hours. Transfering the drive itself is a question of minutes.
The migration wizard offer the option of working with a drive transfered from the old computer to the new one.
Electro, July 2013