Re: What program do you use?
MyPaint for drawing and Paint.NET for fast sketches, pixel art and so on.
MyPaint is probably one of the best freeware drawing programms. It is really easy in use, has some nice options and really great set of brushes. One of best things (depends on your preferences - for me it's great) is easy changing of canvas's size - you just resize window. There is a limit of drawing space, but it sure is big enough for most users.
It lacks many tools found in other (freeware and not) software, but it's still enough if you only need to draw. It surerly is not programm for professionals.
My rating: 4,7/5. I'm still waiting for next updates of MP

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Paint.NET is great freeware tool for anyone who doesn't want to use it for drawing - photomanipulation, editing pics, etc., yes, but not for drawing - Paint.NET lacks any pressure-sensitive brushes and similiar options.
If you are pixel artist, Paint.NET is going to be useful - big zoom scale, 1px brush (pencil, most of time and brush/filling tool for filling

), many layer modes (if you like to play around with interesting effects) nad 1px rubber (yay and yuppie) :>. For it's enough to make neat pixel art. Then you can use your own sprites for RPG Maker XP (I still mourn for VX version - they deleted XP's awesome tilesets system and put a new crappy one)! Back to subject...
Paint.NET is also useful for manga scans editors - Paint.NET lacks some text editing options avaiable in Photoshop (I don't know about GIMP, I don't use it too much :<), but can be helpful in cleaning lineart and fixing contrast etc.
Enough of it

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My rating: 4,9/5 - it would be great to see some major changes in brushes (pressure-sensitive brushes :<<!) and text editing tools - they are just basic ones and adding some more advanced would be great :>. Also, I miss color to alfa (just priceless when working with linearts and manga scans).
I guess it's all ^.^.