I had two favorites, the Summit on Celebrity (which isn't doing it this year) and the smaller Regent ship. BUT ALASKA certainly is one of the most popular destinations for cruisers. I believe there is a plan for Cruise Freek's to have an Alaska Group which makes it extra special to cruise with other CRUISEFREEKS on board. I have to look and see what it is going to be. It could be a Princess one if I remember right! Princess has had many years of cruising in Alaska and has it down to a science when it comes to their excursions and tours. Their ships are very nice ships too.
Having the ship you pick go into Sitka and Glacier bay both is something I recommend when you choose to cruise Alaska. Sitka is the old Russian Capital and the National Park of Glacier Bay is very special place to enter by Cruiseship to see and hear the calving of the glaciers! WONDERFUL place, I hope you can go!