Depending on how much effort I want to put into my lunch breaks, I'll either reach out of my gigantic bin of bargain-priced Top Ramen, or go for a dollar pack of the Chow Mein brand noodles as it has a few more steps than just a flavor packet. With the Chow Mein, I usually shoot for anything Teryaki or Spicy, chicken or beef depends on my mood. Having said that, my absolute favorite is the Thai peanut.
If I'm at home, I'll experiment a little bit with the Top Ramen: poached or hard-boiled egg, chopped celery, minced garlic, cubed carrots, red peppers, or basically whatever I have on hand that I feel would compliment the other ingredients. I've known people who just throw a little bit of everything at once, and somehow it comes out tasting like nothing.
But I'll never, ever go for the 'pre-cooked' udon noodles ever again (I forgot the brand). It makes everything smell and taste like Play-Doh.