Canon 40D

I have decided to upgrade my camera to a DSLR and decided on the Canon 40D. I think that I will probably just go with the Kit lens 28-135IS for starters to learn the camera and settings and what not. But, what would be the best additional lens for shooting from the boat? I do not want to spend a fortune, but do want to get something with image stabilization.... and any recommendations as to where the best place to get a really good deal on it is???? Also, what other items will I need to get besides a carrying case and CF memory card... Any suggestions/recommendations would be appreciated...