Cloning a laptop drive is no different than any other drive. I do it regularly using Acronis TrueImage 10.
I set up an external drive 160 GB. Connect it to the laptop and boot with the Acronis bootable CDR. I then clone the internal drive to the external drive. Both are the same size. When it is done, I remove the laptop internal drive and put in the replacement. Drive RPM is not a factor at all. I use all 160 GB drives (5400 RPM).
I then clone from the external to the internal using the same procedure. When it is done, I then have TWO main drives for the laptop - each identical to the other. That is system backup to the nth degree.
It is also possible to clone directly to external cases that can accommodate 2.5-in drives. Best results are via eSATA, then Firewire, then USB 2.
BTW - I just did all of this with a new Thinkpad T60. Super little machine!