Upon the suggestion of a family friend (after she got her own tablet this past Christmas), I've been very impressed with the free drawing software from Japan, FireAlpaca! It's a lot of fun to use. It's a simpler version of Photoshop, but I'm impressed with the selection of brushes, which superbly works like their real-world tools (pen, pencil, watercolor, etc.). I've done a couple of tests in FireAlpaca on my tablet, and I love them.
First, Lily Merriweather, done December 26:
And Rekira, done on December 27:
More to come by year's end!