Advanced students would be the only ones to benefit from activities using RealVideo.
News are hard to understand unless the students are familiar with the vocabulary.
Commercials are a good starting point to work with comprehension, and at the same time, the students have a direct relationship with the culture. The sites are excellent to appreciate the differences in pronunciation between the Spanish spoken in several places all over the world. So, unless you are familiar with the differences in pronunciation, don't assume that a site from Mexico will offer only Mexican programs.