Well, I hope I don't have to move. But, if things don't improve, it might have to come to that. I've tried different types of earplugs and even managed to figure out the correct way to insert them (thanks Logan5!), but I'm really prone to inner ear infections and can't be inserting things into my ear canal all the time. Plus, they don't block out everything or help with the cigarette smoke problem.
I finally broke down and called my landlord this afternoon, though, and it turns out that I'm not the first neighbor to complain about this particular tenant. I'd been afraid it might just be me because I've always been noise-sensitive, but it turns out my other neighbors don't like to listening to Lady Gaga blaring and drunk underage kids being loud until 3 am, either. Go figure!
She said she'll be speaking with her again and, if it continues (like I'm guessing it will), she'll be forced to start the eviction process. Although my landlord didn't get into details, this girl and her parents, who helped her get the place, were not truthful about some things on her rental application and the landlord has reservations about her living there anyhow. So, part of me is skeptical things will get better, but I'm praying.