The only time I absolutely MUST wear my earbuds and listen to my iPod is when I am mowing the lawn on my riding mower:

1. Layer one - earbuds
2. layer two - dust retarding bandana
3. layer three - sound deterent full-body headphones (used on rifle ranges)
4. layer four - sun bonnet (like the ones worn in pioneer days) to keep sun off face
5. iPod stuck in top of my cowboy boots (not really - in my jean's pocket)

(I know Apple is secretly trying to track me down and use me for a Tv commercial in this get-up)

Other than that, I can function without my iPod in most situations, especially while on my bike.