How can I prevent my music apps from launching and playing on their own?
After doing some more research, I found a thread with a lot of users having the same exact problem: 

Their solution is to use either Headset Blocker or Disable Autoplay apps. This seems to have sort of worked. Just make sure that taskkiller isn't disable either of these.

I am still experimenting on how to fix this issue... 

Edit1: I still see the same issue even though both suggested apps are running. I believe the taskkiller app may be causing this issue. I am going to try disable it and seeing if this gets anywhere.

Edit2: Still no luck. I am going to try rooting my phone and installing the Autostarts app