Alaska. Princess is outstanding, and they can get you into Glacier Bay. I've heard good things about Holland America too. Do the one way, regardless.
If you've got some extra budget room, strongly recommend balcony because the scenery you can enjoy from the comfort of your own balcony is extra-spectacular on that side.
The train ride to Denali is pretty good too with good facilities, but you can do a lot on your own out of Anchorage with some planning.