Alexander Calder has been my favorite artist for more than 30 years. When I was in college I wrote a paper on a mobile that was displayed at the Cincinnati Art Museum at that time. I love his bold use of solid colors and dynamic shapes, the way he used line/shape to suggest a figure or an animal, the magical balance he created with his mobiles (and stabiles)... his take on positive/negative space, light, shadow and line - especially with the incredible wire work of his circus sculptures, and of course, his jewelry. Oh yeah, I'm a fan.
Most everyone has probably seen at least one or two of Calder's works, but in case you're not familiar with all the wonderful things he did, you might like to visit the Calder Foundation web site where you can enjoy some of his work you may not have seen before.