I have just migrated to Ubuntu a few months ago, and find myself wanting Illustrator again. What is the best alternative for vector based drawing? Can Gimp do vector as well, or is it mainly pixel based like Photoshop?
There is also a helpful guide on using Inkscape for Illustrator users.
Inkscape is a good alternative, and if you want more complicated vector graphic, you could try Torapp guilloche designer, it is free and runs in Chrome 20 and above. No installation and plugin is needed.