i've got a hp notebook running xp.  it's about 5 yrs old, but a couple TIMES a year, i save my stuff, STICK in my xp cd, delete everything, and reinstall xp and all my programs.  this has worked out GREAT.  my computer keeps clean and running very well.  but i'm tired of doing the extensive PROCESS.  it's; install xp.  update to sp1.  update to sp2.  update to sp3.  update everything else!  install office and my other programs.  tweak everything the way i want it.  this is very time consuming. 
is there a way, to get my computer set up just the way i want it, then make a mirror IMAGE (like on my external usb hd) of the drive.  then, next time i want to do a clean sweep, just install some other "xp boot disk" and wah lah!  back to where i want to be without all the frustration of doing it step by step.  also, idealy, i'd love to be able to do it all from my usb hd.  boot from it, install xp from it, and have it install itself back to it's "safe clean slate" point.  any ideas?You used to be able to use Symantec Ghost but I don't think it any longer supports USB drives (I may be wrong)

My advice is use AcronisGhost does support USB drives so your info is innaccurate...
However as advised i would choose Acronis over Ghost anyday...i have both.
For safety purposes you're better off burning the images to CD/DVD instead of STORING them on an external drive...after all ALL HDD's fail sooner or later.