One of my very favorite soups has got to be caldo gallego, a Spanish soup (from Galicia, hence the name) which consists of sausage, potatoes, kale or other hearty greens, onions and white beans.  A similar soup appears in Portugal, where is is called (I believe) caldo verde.  I made some last night, and since my buddy Greg asked for the recipe at lunch today, I thought I'd go ahead and post it.

start with broth.  I use Pacific Food's "Natural" beef broth.  It has a great flavor, and no added junk.

throw in

• onions (chopped)
• kale or other greens: I like "lacinto" or "dinosaur" kale, which has thin very dark leaves.  I've also used oak leaf kale, regular curly kale, or collard greens to good effect.  I've seen some recipes that call for turnip greens, but I find them too bitter.
• sausage: the best bet is if you can get real Spanish chorizo (the hard kind, not the squishy Mexican kind you often see in markets here).  Since I don't have a regular source for those (although occasionally if I'm in Seattle I stop by the Spanish market at the top of the Pike St. hill climb) I use a hard smoked andouille that my New Seasons carries.  I've also used Polish or Keilbasa, but it's not as good.
• Potatoes: I actually have started substituting tofu instead, being opposed to simple carbs, but I've used white potatoes or yellow fingerlings (the absolute best if you eat taters). 
• white beans: navy beans are nice, or great northern.  I think I used great notherns from Westbrae Natural last night.

Bring to a boil and cook until the kale is softened up enough to eat.  Goes excellently with some extra tabasco dashed in at the table (if you like that kind of thing).