Fruit of the Loom white briefs is my #1, especially the vintage waistband, blue and gold no lettering.
Then Hanes white briefs, although again, especially the vintage red, gray & black stripe no lettering. (super soft after a few washings too)
Next is both of those in boxerbriefs and then a few other briefs like Jockey, Champion, Tiger (doubleseated), old style CK and a few more off brands.
For the ones wondering what it is about the waistband or maybe even tighty whities all together, and why not the designer/expensive brands...
I think, for me, and I mentioned this in another forum, Fruit of the Loom and Hanes originated in a time when underwear was just that, "under" wear. You weren't supposed to see them in public. Unlike the designer brands, which were created and marketed mainly for that trendy purpose.
I always (and still do) wonder what type of and brand of underwear a guy, I might be attracted to, usually wears. It's the mystery of something "under" something, unseen.
When you catch a guy bending over or he's shirtless and suddenly his jeans or shorts sag some, or you look up at some house construction in the summer and see a suntanned muscular guy on a roof shirtless and sweating and bending over to nail some roofing down and you get that quick sudden shot of white hot waistband and hopefully even more of them, or the dude in the office wearing a white dress shirt and bends over in front of you at the copy machine and you can see through...well...some of you guys know exactly what I mean. Which is also why I like the slow strip in a porn or ha! real life...and not the ridiculous fully clothed guys to BLINK...naked! That's boring...no real foreplay.
Plain white tees play a role in all this for me some too.