What piece of running gear is your current favorite? All-time favorite? Obviously, shoes are the most important but let's not talk about shoes on this thread, that is already the focus of the "Better Shoes" page here on Letsrun.
For me, it has to be my ancient but reliable iPod Shuffle. It is the size of a postage stamp, holds 500 songs and 8 hours of podcasts. Thanks to that thing, I have probably run 50% more mileage the last couple years. After 35 years of running, it is great to be able to listen to podcasts (or music) while grinding out the mileage.
What is your go-to, favorite running related piece of equipment or apparel?
p.s My all-time favorite has to be my trusty Timex Ironman watch. I think I took a million splits on that thing. I still love it even though I run with a Garmin now.