What is a good internet package for this situation?

I am about to move and I am trying to figure out which internet speed I should purchase. My roommate and I both play PC games (COD, WoW, Lol, etc.) and would be doing so at similar times during the day. We both also usually have at least 1 internet window running with music or Teamspeak. I have a 7Mb/s connection at my house currently and when more than one person uses the internet or plays a game the connection suffers. I have narrowed it down to pretty much 12 or 20Mb/s but I don't want to pay the extra for the 20 if I can use 12 without any issues. Any input is appreciated.