Thinking about some anime series earlier today made me think of this one for some reason. I actually really liked Shounen Onmyouji when I first watched it and through subsequent watches.  Took me the longest time to figure out the OP was composed by Yuki Kajiura (which isn't surprising now considering the tone of it - her compositions have a similar feel and tone, as well as the artists she works with).

 

I'll probably give it a rewatch when I have more time, but this brought back memories.