Applications :: ITunes Deleting Music That's In A Playlist?

I have a fair bit of music in iTunes, and it has bugged me somewhat that often when I want to delete many files something it's easier to go into a playlist to find them. But when I delete them from there it only removes them from that playlist, not the computer. I guess this makes sense, and I suppose nowadays space isn't often a problem.

In case this isn't clear, what I want to do is go into a playlist, then select songs, then delete those songs from my hard drive.