I think I prefer the shot leveled out, myself. Not just to level the water but to balance the gull a bit, as well. He looks as though he is leaning forward a touch.
As far as color, DOF, composition, light, story, etc... I think you nailed it. On my monitor the color looks great. As Janice said, the DOF works very well; blurred just enough. The exposure looks just about perfect. He may be a tad blown out on the shoulder, but with all of that white it's hard to tell. I like the composition. I think you placed the bird well as to frame him with the space needle and skyline.
All around, great image.