I think "anime" based music is like 90% of my sound collection. Many of the top orchestral composers make songs for Japanese animation. It's kind of funny how I found my way here, I was a hollywood movie soundtrack (orchestral score) nut and I looked at some of the other works in their resume.
Great instrumentals, professional singers, epic movie sound-track style scores (think The Rock, Gladiator, etc). You can keep this kind of music on whether you are doing critical listening or sitting back and reading--it's all very nonfatiguing.