Must-have Canon lens for Galapagos?

Hey all-

We are headed to the Galapagos this year. I've got a Canon 5D in a Subal housing. For those of you who have been there, what is your favorite, most-used lens of the trip? Also, what did you use most top-side?

Thanks for the input!

Just got back from an Aggressor trip around the Galapagos 2 days ago,

I shoot Nikon, but will give you an idea of good focal lengths.

Most used wide angle: 12-24DX

2nd most used WA: Tokina 10-17 FE

also used nikon 18-70 (would have loved the 17-35, but didn't have the $$ yet)

Also liked the Nikon 60mm macro fro Cousins Rock (great macro site)

For land a long lens like a 400mm is great, I only had a 300mm and wanted a little more reach sometimes, also a mid range zoom (like the 18-70mm) is useful.

I also used my macro lens for great head shots of Iguanas, Turtles and Crabs. I'll try to post some pics soon.

The Hammerheads are quite shy and good head shots require a linger lens, I often shot at 70mm as they flew overhead, but I didn't dare put it on until I got the whale shark shot, which the 12-24 was perfect for.

Enjoy, it's a trip of a lifetime!

John