Building a full-size stereo headphone amplifier

The title of this blog clearly reads 'Tilpo's music and audio', but so far I have only been concerning myself with the 'music' part. I'm going to put an end to that and make my first audio related post. Bear with me.

Background info: About a week ago I finished my first DIY audio project; the adorable Mini³ designed by Ti Kan of AMB labs. I chose to build that specific model because there is lots of documentation on it, the parts are easily obtainable and portability is great (fits in pocket). The construction went without a hassle, apart from some slight issues with the positive battery contacts.
After my little project I got the confidence to start on something bigger. Instead of a pocket-sized portable amplifier I will be building a full size stereo headphone amplifier. I collected some money together from birthday funds, and I was ready to go. I first needed to select the right project to build though, and following will be my process of choosing.

The insides of a magnificent Beta22