Music from other games in siegelets (and heroes)

Hi, guys. The title pretty much says it all. I would like to ask, what is opinion of the community on using music/sounds from other games in custom DS maps? I would like to use music from Empire Earth or Serious Sam 3 for example, but I would hate to be banned from the community for violating copyright rights. How do you feel about this? Is it allright, or should I avoid that?

Also, I was planning to adress mod creators, but since I'm already posting this, can anyone advise me on how to legally use playable gargoyle/elfgirl/goblin/orc/etc from heroes_compilation in my custom DS1 map, should I ever release it?

Thanks in forward to anyone taking their time reading this!