I use Paint Tool Sai 99.8% of the time. I use MS paint in some situations or if I don't feel like dealing with layers.
Sometimes I use Photofiltre too, it has some really good textures and brushes on there! :U (I use the photomasque list
I used to draw on it but now I just use it for effects. I can do spectacular drawings on that program but it takes a long long time to color and its much harder, because unlike Sai, which has the infinite reverse tool, it only undos your changes 7 times so if I forget to add something in the background, I'm screwed if I forgot to copy and paste it and save it somewhere else.
Sai has some good brushes too, so I don't use Photofiltre that often. MY MAIN ACCOUNT:
If you want to chat or contact me somehow and need a fast reply then I'd suggest posting there instead of here. I only log on here to upload my Wolfquest crap. :b