One of the things I disagree with the author of the webcomic "Set Apart" on is the issue of whether instruments should be used in worship. The author, Adam Humphreys, takes the "no" side. I will be quoting from his page.

I believe that instruments should be used in worship, as well as singing. I feel that Psalm 150 conveys that it is allowable. But ALH says on the third paragraph, first sentence: "Many people will turn to Psalms to justify the use of instruments, but this was a command to the Jews under the OT". OK, but aren't those things that were part of the old covenant symbolic of Christ? (Colossians 2:16)  All right, I understand that you should do everything the Bible says. I understand that Christ did away with the old covenant.