... Gordon said about Glacier. If you haven't gone to either Yellowstone or Glacier, go to Yellowstone first. It's a wonderful place but Glacier will spoil you!
For a slide show from my '98 (first) trip to Glacier, go to
http://www.lhrimages.com/pictures/np/gnp/ . Just note, all the pictures in that slide show were taken with disposable cameras (35mm and panoramic) so the quality is a little lacking. I have better pics from my '99 trip (using an Olympus Stylus 140 -- advanced point and shoot) that are better but alas, I don't have them scanned and uploaded yet.
Have to go again with my SLRs so I can get even better pictures
Larry