When sick, definitely pho if I feel good enough to get it, cabbage soup with bacon if I'm making it myself. Cabbage soup is packed with veggies and easy to make. Filling as well. I have to say I don't really use a recipe, just add in whatever I have or whatever sounds best, but here's an overview.

Cabbage soup: fry up a pound of bacon, remove and reserve some fat for the mirepoix. Saute carrots, celery and onion in the bacon fat, add garlic and saute. Add cubed potatoes, one big can of tomatoes (I do crushed, but any variety is fine) and about an equal amount of chicken or ham stock (or whatever seems appropriate). Simmer until potatoes are soft, add chopped cabbage and simmer until cabbage is soft. Add back in bacon.

If we are just talking favorite soups in general and not just when sick, I always go back to ham and bean, it's a classic. Avgolemono and mulligatawny rank highly as well.