Would the big upcoming Alaskan cruise (in a week and a half) call for a 70-300L? My current gear is a T1i, Sigma 17-50, Canon 100 2.0 and 200 2.8II (and the associated goodness for waterfalls, bright light, etc.).
Also, would wildlife in bright sun necessarily call for a polarizing filter in many cases or are polarizing filters more of a landscape thing?
I live in Juneau and recommend either the 70-300 or maybe even better the 100-400 (the 100-400 is my go to whale lens when I'm out on my boat and my handheld bear lens when I don't have my 500 with me or the bears are too close).
And yep, a polarizer is good to have. Don't forget it can also do a very good job accentuating rainbows!
Feel free to ask any SE AK related questions if you have 'em.
I hope you enjoy your trip, the weather gods are kind and the whales, bears and eagles plentiful! (the wildflowers are going crazy right now!)
Cheers from warm (!), sunny (!) SE AK