Storm Spirit Sombrero
Okay, this one's a little more open to opinion. Most absurd/random/silly equipment ideas get thrashed pretty quickly in Dota 2's Steam Workshop. Dota 2 is serious business and most fans don't see room for silly humor in the game's no-nonsense world. The most common comments found on silly item suggestions like monocles, top hats, and butterfly wings are "leave this stuff in TF2" or "don't make this LoL please."
Creator Crocodile Dendi makes a decent argument justifying the sombrero's inclusion, however, pointing out the Storm Spirit's back story emphasizes his "good humor" and he's described as "jovial" and "jolly." Whether or not that'll actually make you feel better about sombreros in Dota 2 is up to you.
Vote for or against it on its Steam Workshop page