I am going to be auditioning for RENT soon for the part of Mark, and am struggling to find a good audition song.

I'm guessing that singing anything from RENT itself is a big no-no, and that everyone else will probably be singing songs from Tick, tick... Boom!, Spring Awakening, so it might be best to avoid those shows. Thoughts?

Are you kidding me? This sounds like a major audition for you. Why would you ask a group of strangers for help? Nobody here knows your range or style. This is a personal decision that you need to make on your own - or at the very least, with the help of friends or teachers who know what you can do.

If I may, from past experience with friends and family members auditioning and/or performing in RENT, a pop/rock musical theatre type song that shows your range in the style of RENT is fine. Yes, it's is a good idea to sing something that is not from the most current shows like you listed, but if you can knock one of those songs out of the park that makes the CD sit up and take notice, then go for it. Most musical theatre actors have songs that they are passionate about, so choose one you absolutely love that is the right genre and sing your heart out. You can't hold back with RENT since it is a vocally demanding show!

Break a leg!