When you ask for software that’s “not impossible to use”, what do you mean? I use Adobe’s Creative Suite CS3 and it isn’t impossible to use.
What is the end goal of the projects you are creating? Do you need to share files with other users?
When you refer to design/drawing software, I think those two are mutually exclusive. One can design in Photoshop or Illustrator, but InDesign is my choice, and is a must for multi-page projects.
Also, one can sketch/draw in Photoshop or Illustrator, but there are also many other software choices more tailored specifically for sketching, such as Alias Sketchpad Pro, and lots of vector-based alternatives if you are looking for that sort of “drawing”.
If you just want something inexpensive to doodle and perhaps do some small image manipulation, I think Pixelmator is the way to go. If you are looking for a vector drawing app, check out these search results on MacUpdate.