Angel with a Shotgun

My favorite platforms for drawing are: Photoshop and Open Canvas. It took some time, but after tutorials and much practice, I am getting the hang of Paint Tool Sai and falling in love with it~

Here are some practice bits:

(Above: Added Effects from: Picmonkey)

(Original pic done in Paint Tool Sai)

Are you using any of these programs? If yes, which one is your favorite? Or are there any other programs that you use/recommend? :D