I heard the cry "ease of use, ease of use" out there among you icon clickers. Relax, please. Now repeat after me "I do not need to make a habit of using the command line unless I want to." And "I disavow any knowledge of the command line but reserve the right to recollect if I need to." It's a good thing we done this because I was going to breakout Imagemagic a command line graphics application that could make you the next Wizard of OZ. LOL we could be down here in the cave of wonders for weeks.
My main infatuation is that you too can turn your average to geek-busting PC into an art studio for a small sum, next to nothing in fact. Yes in Microsoft Windows too. Check out the Open Disc project: http://www.theopendisc.com/ These are MS Windows compatible open source programs compiled into a DVD iso image. You have to download it and burn it. The cool thing is that the risk of malware is not there. Not for the DVD image and not among the apps on the disc.
But hey, I'm a Linux guy, Ubuntu in fact. I will list the rundown of Apps that I am using.
Libre Office is an office suite a fork of OpenOffice.org
GIMP or GNU Image Manipulation Program is like Photoshop - bit-map
Inkscape is like Illustrator - vector
MyPaint is like Corel Panter - sims natural medias
LibreCad is like AutoCad, sort of
Then I have a collection of other apps to round out things like viewers and printer control apps, color pickers.
If you suffer from creative block once in a while. Put as many of your own sketches or reference pictures into a folder, then use a screen slide show function of a viewer to replay them. Sometimes fast, sometimes slow, study them intensely or out the corner of your eye in a casual manner while doing something else (like cleaning your studio). I rigged an old standby PC for this. Add music or not. Things will start cooking again.
Use old technology like a pad of paper and pen to take notes of your thinking. Then scan them into your folder for mental viewing. Pay no attention to the man/mame behind the curtain.