Back in the day, the theme songs to cartoons weren't all that great, but we now have them ingrained as pop culture for the most part. Some songs on current shows are decent, but the rest all seem kind of...blah. Ben 10 is one that I like as it seems to hearken back to those cartoons of the 1980's with the hip, catchy themes. Some shows don't really have themes, but just opening narratives. The Genndy Tartatovsky/Craig McCracken shows have always used music in a great way as far as opening themes as well.