I can't really tell you what to do, per se, because where you choose to attend law school is a highly personal choice. Nonetheless, I live in LA, went to law school here, and worked in the entertainment industry for a while. Perhaps I can offer some insight on the local market.
Generally, you should go to law school in the area in which you want to live, unless you have the opportunity to attend a highly prestigious national school. It is much easier to obtain internships, clerkships, and other positions locally. If you have the reputation of an elite national school behind you, like Harvard, well, that's different. But if you attend a local/regional school like Drexel it might be very tough to land entertainment related internships in LA. Conversely, if you want to live in Philly, it might be difficult to make connections if you attend an LA school.
Even in a big metropolitan areas like LA and Philly, law can be a very local, insular business. I've seen tons of examples of students from small, locally reputable (but not nationally known) schools easily beating out applicants from higher ranked out of state schools. The ability to make connections and to network is highly valuable, and it's tough to do that from three thousand miles away.
Loyola and Pepperdine both have good reputations in CA, with an advantage to Loyola, in my opinion. Lots of attorneys in the entertainment field are Loyola and Southwestern grads, as well as UCLA/USC and Pepperdine. All of these schools offer various internship opportunities and alumni connections with the studios or firms, and offer courses in entertainment law. If you attend school in Philly, you will have to find a way to compete against the local talent from these schools, which may be difficult.
Your uncle is right, in that attending Drexel will by no means permanently prevent you from practicing elsewhere. Drexel is ABA approved, and qualifies you to take the bar in any state. The question is simply one of difficulty. No matter what city we're talking about, whether its LA, Philly, Dallas, whatever, it is very difficult to show up after graduation in a new city in which you have no connections and to compete for jobs against local students who have had three years to develop a network and gain experience. This is especially true if you are not graduating from a prestigious national school, as you won't be able to rely on your pedigree alone to open doors. That doesn't mean it can't be done, but be realistic about the obstacles you may face.
Additionally, if you really are interested in entertainment, you will need to pass the CA bar exam. This is no small task, as it's considered the toughest in the nation. Take a look at the CA bar pass rates from out of state schools, and take that into account.