Simply put: No.
“Straight” men do not like a nice butt without regard to what gender that butt is attached to.
I use the quotations above because straight seems as if it’s being given quite a bit of elasticity in the thread.
If we are defining straight as a heterosexual male in the traditional sense of the word, I think the answer is always no. Straight men are into women and women exclusively. No straight man finds anything sexually appealing about another man.
Sure, some open-minded straight men who aren’t pent up about their sexuality might admit that another man isn’t bad looking or that an especially muscular guy is ‘built’. However this only likely occurs in casual situations where he feels totally comfortable and not the least bit emasculated or sexually engaged.
“Straight” men are just not into other men. Not on today or tomorrow, nor the day after that. “Straight” men aren’t into other men. Period.
The moment a man acknowledges actual attraction to another man, he is firmly ensconced in the bi category. And that’s perfectly ok too. He just isn’t “straight” imho.