Windbreaker

My local magazine interviews minor celebs, and one of the standard features is what are some items that you can't live without. I always imagine that I'd be interviewed for this, and I'd jump at the chance to mention how fond of windbreakers I am. They're so versatile and easy to pack that there's almost no downside to keeping one in a backpack so you're ready for any kind of weather. I know they're not the most fashionable, but you cannot beat their practicality.