Armando - I do this for a living at a rather large enterprise and I can say from my experiences, you only really need to worry about two drivers (Assuming Windows here, don't know enough about Linux or Macs yet). The hard drive driver and the NIC driver. As long as you can get the system up with these two drivers everything else can be retrieved after you get the machine back. The way we accomplish this is to ensure generic drivers are installed and used before making the image. Once that is done, you make the image. Then, whatever equipment they send back, you should be able to place the image back on it and get it booted. Once that is done, just update all the drivers and you are back where you were.
Oh, and the tools I use are Symantec Ghost at work and Acronis True Image at home. They both seem to work well for me. I have only had a corrupted image twice that I can think of and both times they were attributable to the hard drive going bad anyway. Of course there is always the other option not yet mentioned...Get another hard drive to send back to them. Nah, the image can be burned to the disk and is a good archive anyway.
Given that I backed up to DVD, though, I may not be a happy camper when I get her notebook back as it has been noted by Carol that restoring from DVD's with TrueImage is molasses slow. Unfortunately, I wiped the harddrive before I sent it in and reset it to a virgin XP install (I'm paranoid) so it's inevitable that I'm going to have to face this!
Why not just copy the image to your hard drive, slave her drive to your machine, then lay the image down on it there? It is a lot faster, even with breaking open the cases to set it up. Also, I can say from experience, don't shortcut and use a USB adapter. THEY ARE SLOW when trying this. If you want to do that, you might as well go from the DVD directly!