I was going to suggest the same thing as Chris. Squash is about as simple as it gets. You can puree a little apple in it for sweetness if you like. Maple syrup is great with it.
Clam chowder is pretty quick. A bit of bacon, onion and dice potatoes, a can of clam broth and, if you're feeling flush, buy some fresh clams to dress it up. Finish with cream.
Split pea doesn't take too long. If you use canned beans, just about any bean can make soup in no time at all.
Chicken noodle is pretty easy and not too challenging for a beginner. Diced onion, celery and carrot. Poach a skinless chicken till the meat falls off the bones. Take out the bones. Chop the meat. Cook the vegetables in some butter till soft, add the broth and chicken meat. Add your favorite noodle. When the noodle is done, it's ready to eat. You can also cook the noodles separately if you prefer.
Corn chowder is a good fall soup. A bit of cream and a biscuit on the side just because.
Tomato soup is a classic, especially in fall with all the ripe tomatoes. Cook tomatoes, strain out skins if desired, add some vegetable or not, puree, add a bit of cream.
Geez, now I'm in the mood to make soup.