You know that it's possible to backup your CDs with iTunes and your DVDs with Handbrake, but what about that new Blu-ray disc (BD) you just received during the holidays? Macworld has a good write-up of a beta utility called MakeMKV that will rip both DVDs and BDs to perfect quality MKV format.
Bear in mind that this will require having a connected or internal Blu-ray drive that can read said discs. This is currently a bit of a novelty in most Macs being that Steve Jobs considers the whole thing a "bag of hurt." However, if your system meets the hardware requirements, you're ready to go off on your first Blu-ray ripping journey without the typical mess involved.
Macworld's test resulted in a file nearly 32 GB in size as compared to the original 35 GB on the physical BD. While this is useful for those of you with a farm of terabyte-sized drives at your disposal, for others, a lower quality backup is acceptable. If space is a concern, or you want to put a copy on your Apple TV, it's possible to use previously-mentioned Handbrake or Video Monkey to transcode into a lower quality (but still excellent) file.
MakeMKV is available now for free while in beta. The Blu-ray ripping functionality is only free while the software is in beta so grab it while you can. Once the beta period ends, only the DVD-ripping will be free.