I am glad to hear that you liked it also technically, which is my main problem… hehe. Well, I did some shots later, with sunset more advance, but light was to little to have any detail, and I didn´t have tripod, so I had to go for this one, and the man on the boat also moved out of the scene, which made it less interesting. I did some shots from another location by the lake, but they are not that suitable for the assignment, perhaps I will upload them on Flickr.
I didn´t notice the tree, but you are right, it would look better cropping it.
And I use Aperture for my pictures, which I always shoot in RAW =)