Inskcape and Gimp, Blender is very cool programs. Takes a few turns to master them, especially Blender but complaining about UI's is like complaining about other peoples rugs. They might look awkward to you at first, but have another look at them and you may start to like them.
+1 three of the most amazing pieces of software I didn't have to pay for!
Sadly Learning to use blender is like tying to shave your eye balls, but the program is phenomenal in its power!
GIMP is just slow and Inkscape is buggy, though both of these criticisms are aimed at their interfaces rather than the software directly, as I run all three on a Mac and the non native interface is jarring.
