I love a good sunburst. I was photographing on Enchanted Rock in the Texas Hill Country and stumbled upon this cluster of huge boulders. As the sun rose, it started to peek over the edge of one of the boulders. Voilà, sunburst.
By shooting with a really small aperture (i.e. f/22), you can amplify the sunburst effect. You only have a few seconds to shoot, though. You have to keep the sun lined up with the edge of the rock, which means that as the sun moves, you have to keep moving around to keep both lined up.
Sometimes you also pick up a good bit of sunflare. I tend to like that, but your taste might differ.
Canon 1Ds Mark III. ISO 125. 16mm. 1/40 sec. @ f/22. EV -1 1/3. Polarized.