This year we will be using Art Lab for Kids. It actually reminds quite a bit of Artistic Pursuits, but it is way cheaper! There are 52 lessons, ranging from drawing to painting to mixed media. Lots of variety here! A helpful section in the beginning details what you should have on hand to start. In general, the supplies are easy to find. I went through the book in the beginning and added a few key items to my Rainbow Resource order, since they usually have good prices on art supplies.
I think this book will last us for at least two years of art. I confess that we don't get to art every week, which is something I am aiming to change. From now on, I will be making a dedicated effort to start each Friday with picture study followed by an art project.