Sorry, but I gotta give my vote to "With or Without You." Sure, it's without a doubt the greatest bittersweet love song every made, but "Steets" just does something to me. I totally get wrapped around it's organ intro, and when Bono sings "I want to run" it actually makes me feel like running out in the sunlight. I personally don't think there is any other song that feels like an auricular cleansing of one's spirit/ aura/ whatever.
Pfft, I just think the song is really really really fantastic