My favorite soup when I'm not feeling well is ochazuke, a Japanese soup made with tea and topped with salmon (in my version). It may seem weird to have fish in a get-well soup, but it's perfect-- the key is not to put too much in. The combination of soothing broth, rice, and salty fish is perfection.

I've been felled by the flu myself; when my daughter first came down with it, I had the foresight to make a big pot of chicken soup (1 lb peeled parsnip chunks; 1 lb peeled carrot chunks; 1 lb peeled onions, sliced in half; a whole chicken or the equivalent in chicken pieces; water to cover, simmer for a couple of hours, remove veg and drain broth of impurities, chop meat).

It clears my sinuses like nothing else.

Add matzo balls (can't abide soggy noodles, and can't eat rice) and some chopped parsley.

p.s. Hot and Sour Soup from a Chinese takeaway (the deluxe kind with extra vegetables), or some Vietnamese Pho (or Chicken Sour Soup) are also fantastic.

Tom Yam is a big hit: the herbal combo of galangal, lemon grass and kafir lime with the chile hit is good for clearing out the sinuses.
Matzoh ball is a classic, the richer the broth the better, and don't hog the salt shaker, I need it too.
Hot and sour (chinese) is less frequent, only because there are a lot of versions, most of them less than stellar -- again the broth must be of the highest quality

I just got home after a two-week holiday travel marathon, and the FIRST meal I made was this (Chicken) Noodle Soup. It's easy to make, full of veggies, and wonderfully comforting. I make mine without chicken (I'm fickle about meat in soup) but it can easily be added in. I also can't wait to make another batch of Butternut Squash Soup in the coming days!

Feeling like I've developed a beer butt after the holidays, we've been staying warm, healthy, prosperous, and satiated on very simple white bean escarole soup--it's more brothy than just beany. And no meatballs or sausage added until this beer butt is gone!

I'm not a huge soup eater, even when sick, but the best one for a really bad cold in my mind is Penny Soup from Joyce Goldstein's Sephardic Flavors: Jewish Cooking of the Mediterranean. The only ingredients are lemon, egg (whisked in so it just thickens the broth), orzo, and broth. So damn refreshing and soothing for a bad sore throat!

Oh, and here's the recipe: http://bit.ly/ZXUIry

I'm in love with sopa de ajo (garlic and bread soup), both when I have a cold and, often, just when I want some comfort food. Here's the recipe I use (and love): http://www.seriouseats.com/recipes/2010/05/sopa-de-ajo-garlic-soup-recipe.html

Oh boy, these all look sooo good my tummy is rumblin. Tom Ka Gai soup is also fantastic and nice and thick from the coconut milk. (I hope I spelled that correctly...)

mschatelaine....about soggy noodles in chicken soup....
I learned this from my mother:

-Cook the noodles separately. Then pour the soup over individual bowls with some noodles in the bottom just before serving.

A fresh batch of noodles can be cooked up to eat with leftover soup OR store leftover noodles in a separate container and then heat them up in the soup.

I love all kinds of soup! I make a twist on your every day chicken noodle soup (my white bean and chicken chili) and it seems to do the trick! Anything warm on a cold day (or when you're not feeling well) does the trick! J

Best get-well-soon soups: matzo ball soup, pho and a warm Indian yogurt soup called "kadhi" (filled with ginger, cloves and green chillies).

I love making this Healing Chicken Ginger Soup when I'm sick. My husband and I always feel better after a big bowl of it. And now I always put ginger in when making chicken stock because of it's healing properties and delicious flavor. This is the recipe that I use: http://www.nourishingmeals.com/2011/02/healing-chicken-ginger-soup.html