It does look beautiful! I didn't mean to discourage anyone from trying it out. I just remember hearing/reading that it is not updated very regularly, but hey, I used an LTS system for way longer than I should have and I was perfectly happy with it. It's not always about having the latest, must updated software. Maybe you want something stable, or something that looks nice and works. To each his own, I say.
I'm also excited about the Cosmic DE! My issue is that I try to not change my system unless I have too, since I use my computer mainly for work and loosing a couple of days setting everything up is more work that it's worth it for me. So I don't know when I'll get a chance to try it out.
Calibre is great for book management. I use Thunderbird for my email/calendar since I'm on Linux and have never even though of changing. Works like a charm and it does everything I need it to.
Other software I use and recommend are: