Re: SLR LENS for Antartica 2009!
Right after seeing some review on the 15mm not so good, I kind of changed my mind on that lens, is better just to upgrade the 70-200 f.2.8. A laptop would save the need to have anything larger than 14 gb. Do you have any sample shots taken with the polarizer? Is it really that bright there to use polarizer, If not used right your picture can come out worse then if you did not use one.
The IS version of the 70-200 f2.8 is a fantastic lens and would certainly help when you are shooting from a zodiac, if you are planning to upgrade to it. I agree with you about not wanting to distort your landscape shots of bergs (although in your first post of this thread you did refer to possibly buying a 15mm lens...!)
If you are shooting both RAW and JPEG, then you are going to eat up your 14Gb of memory cards very quickly. Unless you are prepared to delete shots before you get home, to free up some space, I'd recommend taking some more memory - there are basically no shops in Antarctica, and memory cards are relatively cheap compared with the cost of your trip.
Finally, on the circular polarizer - a lens hood minimises flare but makes no practical difference to the effect of this filter on the light hitting your camera sensor. You will be shooting in a very reflective environment (bright sun, ice, water etc) and so I'd certainly recommend packing one in your camera bag, even if you opt not to use it when you get there!
I look forward to seeing some of your shots in the gallery next year on your return...!