All of the above mentioned are great choices. And I love his voice in most songs, but I'm going to go with a B-side that I've always LOVED the way he sings in it. I don't know if his voice is "perfect" in it, but IMO, he sings the absolute shit out this tune!
If you're talking about "gives me chills/almost makes me wreck my car/melts me into a puddle of goo" perfection, then it would be Your Blue Room & Beautiful Ghost, hands down.
As for songs that you don't have to be a hardcore fan to know, I'll go with Ultraviolet or maybe Magnificent. Possibly WOWY. AIWIY is really good, too...
I don't know how to address "best" or "most perfect" but I think my favorite vocal moments of Bono's are A Sort of Homecoming, Red Hill Mining Town, One Tree Hill and Heartland. If forced to choose one, Red Hill Mining Town.
Yup, like NSW, not sure how to quantify this, but all the ones on his list, especially Red Hill Mining Town and One Tree Hill are chill-inducing for me every single time.
I had to think about this with all the songs Bono has sung with and without U2 (no pun intended). Night and Day, Heartland, and Red Hill Mining Town win my votes. However, if you are asking about pure emotion, my vote is for "Once in a Lifetime", a song he sung with Clannad in the mid 1980s...
Both combine everything I love about Bono's voice: the soft earnestness, the vulnerable falsetto, and the screaming passion. The vocal transitions between falsetto and scream beginning at 2:08 in the "In a Lifetime" video makes my head shiver.