I love Onenote, use it for everything from story ideas, character lists, research etc to storing writing advice, cover note/bio/synopses, lists of publishers/agents, subs sent...

I love that I can work on it on my laptop, phone and online if I'm away from my computer. The layout suits me. I find it easy to work in, much better than Evernote, which had too many bells and whistles for me.