Pre-photo excursion, I have a choice. Which camera body, and which lens? I could bring them all, like I do for photography jobs, but I find that carrying all that stuff takes away from fun when I am on a casual outing. Today I opted for the lightest equipment: the Rebel Xti and 50mm f/1.4.
This prime (ie fixed; no zooming here) lens makes for beautiful portrait style photos. The bokeh (Blurriness of background) is so great - makes the foreground so crisp. The colors come out richly, and you can see even the texture of black fur. Notice how that spots of light in the blurred background come out as circular shapes, rather than octogons, or some other polygonal shape; that's a mark of a better lens.