Power conditioners sound fancy and expensive, but they're really not. They cover several power related jobs, including voltage regulation, noise reduction, and surge protection. For a home studio with limited space, this is a great way to remove some problems from your tracks before you even start recording. Even if you don't currently have a problem with noise from your power setup, prevention is often much easier than trying to edit out a noise.
You can read more about power conditioners here: http://www.prosoundweb.com/article/in_the_studio_whats_the_deal_with_power_conditioners/