I use a series of craft organizers modified to use for my supplies. My favorite are the ones that have built in rows, but the spacers are customizable so you can chose how long you want it to me. In one small case I carry my pencils, sharpener, charcoal, white pastels, vine charcoal, conte crayons, erasers and graphite sticks. I have no idea what brand mine are, but I bought it at Joann's crafts store. You can get them at wallmart as well. My paints are in a small tote box with a handle, same with my inks (as well as one of those organizers for pen handles and nibs, etc that fits inside the case).
It's really up to how organized you want to be. Everything I have is organized to the T, so I LOVE customizable organizers. Chances are you won't need EVERYTHING on the same day, I never do, So I bring that I need (always knowing where it is because of how organized I tend to be). I've seen people use tackle boxes, art storage boxes that are basically tackle boxes, makeup boxes, large tin boxes, and just shoving everything they need for the day in their bag. I have issues with the idea of tossing everything together and letting it mix. Some people don't care though. But that's why everything has a conveniently sized box for all of it's like supplies.
Most importantly get a back pack, or tote bag that will be suitable for carrying the things you need. that way you can always put all of your boxes of stuff in it as well as your sketchbook. Any large sketch pad or canvas should be transported in a portfolio case. Some are expensive, but it's a wise investment you will use a lot.