I'm in the denial camp. (I have some sniffles right now, but I'm chalking them up to allergies, or because I didn't get much sleep last night, although I know I started to feel a little tickle in my throat last night, but we'll ignore that symptom for now!) I try and power through because of course I'm young and invincible, right?
Then after a few days of misery, I finally decide maybe I'll finally take a little cold medicine. I tend to like the orange flavored stuff
Lots of cups of tea. I usually keep puttering around, but if I'm really exhausted I usually just sleep. I tell myself I want to watch some movies or TV, but I inevitably plan a whole marathon and get about 5 minutes in and then zonk out
a little rice porridge is a nice comfort, too, although probably pretty minimal nutrition value, but lots of nostalgia value