Media Center was getting slow to launch again and I did some further troubleshooting. I first created a new blank library and found that MC launched instantly. I then switched back to the original fully populated library and found that it too launched instantly.
I captured logs from the original slow load and from the quick load after switching from the blank to the populated library. These files are attached for review. The file named "LogMainDB" was captured before creating the blank library. The file named "LogMainDBReload" was captured after creating the new blank library and then switching back to the original library.