I don't usually listen to songs by seiyuu outside of their performance on anime theme songs that I like, but I have to admit that I have taken a liking to one tune by Kana Hanazawa（花澤香菜）. Mind you, she is already fairly well represented on "Kayo Kyoku Plus" through her anison.
"Brand New Days" from her "25" album of February 2014 has got a nice 80s New Wave-ish beat to it, and she demonstrates what is probably the most kawairashii example of scatting and rapping that I've ever heard. In fact, I think "Brand New Days" has got some inspiration from Scritti Politti's "Perfect Way". The song was written and composed by music producer and drummer Hiroyasu Yano（矢野博康）. The album broke the Oricon Top 10 by peaking at No. 8.