Two of my favorite spaces are the LA Convention Center and the Getty Center. The LA Convention Center because of its fantastic use of glass and natural lighting. At other convention centers I have found they resort to harsh fluorescents that makes the space not enjoyable for long periods of time. However, the main areas of the LACC are well lit during the day by sunlight and makes walking around for hours far more pleasant.
The other space pictured is the Getty Center. While beautiful works of art can be captivating, having a garden in the center of the space is helpful for offering an eye break and a chance to recharge. The value of natural spaces is well worth the space they demand, even if the structure is in a dense urban center. The Getty Center is outside of downtown Los Angeles, but is atop a hillside where there is not the most real estate to work with.