Harry and Ron fall in love with Ginny and Hermione respectively because of their strength and cleverness. In the case of the former couple, the film of Half-Blood Prince includes a scene where Ginny shuts up everyone trying out for the Quidditch team, by shouting them all down. Harry is noticeably impressed.
Downplayed with Cho Chang, but a big part of Harry's attraction to her is that she's a very talented Quidditch player.
In Quidditch Through the Ages, the captain of a team defeated by the all-women's Holyhead Harpies knelt down on the pitch and proposed to their captain, who promptly cold-cocked him with her broom.
The Heroes of Olympus: Demigods tend to lean this direction, since they're frequently in mortal danger. Percy Jackson clearly feels this way toward his girlfriend Annabeth Chase for an easy example. One of the short stories has Percy momentarily Distracted by the Sexy mid-fight scene.
Many in Honor Harrington. For instance, Sergeant Major Iris Babcock, RMMC, is not particularly attractive. But her truly incredible badassitude note as in, she can throw the title character around the mat with absurd ease, and the title character is a black belt in the martial art they are sparring in leaves Horace Harkness absolutely speechless. The next time either one of them shows up in the narrative, they're married.
The title character herself becomes the object of her future husband's (himself a legendary admiral, but not known to be particularly physicalnote well, unless you put him into a centreforward position and let his left foot shine) attention in part because of this: in a discussion about teaching him her martial art, he demurs and states he'd be quite happy to hold her coat if anyone ever got close enough to attack them.
Ward from the Hurog duology is one of those. He is smitten with Tisala, who is very tall for a woman, probably stronger than most men, and a veritable badass. He is aware that most other men probably would think her too tall and not delicate enough, but in his opinion, she's the most attractive woman he ever met.
In the second trilogy, Wayne is attracted to women who could flatten him if they wanted to (it's implied that becoming an abusive husband is a deep fear of his). Hence his infatuation with Ranette, whose usual response to him is gunfire, and later with MeLaan, who is a nearly immortal shapeshifter.
She had clawed her way to power in the Coast fraternity by a piratical genius and ruthless ferocity that had made her the toast of women's liberationists all along the Main. Her fellow sea-wolves respected her, had astonishing fantasies about her, and went in terror of her...
Asha Greyjoy, from A Song of Ice and Fire, is lusted after by half the male crew of her ship and even her own brother before he recognizes who she is. Note that she can raid and pillage with the best of them.
In the sequel, Legacy of the Dragokin: Benji has a crush on General Lydia and wants to become a hero partly so he can be a Battle Couple with her.note the other part of his reason is to emulate his mother.
Cordelia Vorkosigan gained her husband in the midst of a war by impressing him with both her brain and her martial prowess.
Droushnakovi is a female martial artist whose husband is not the least bit intimidated by her and instead finds her skill attractive.
Elli Quinn and Elena Bothari, of the Dendarii Free Mercenaries, also gain male attention not just for their looks but for their physical aptitude as well.
Miles himself has a thing for Amazons, given his relationship and infatuation with the aforementioned Quinn and Elena, respectively. Also, his occasioRnal flings with Sergeant Taura are noted by a friend who calls it "mountain-climbing."
Tobias from Animorphs falls in love with Rachel because she is so brave and self-confident and she is the best fighter. But unfortunately their lust for fighting also affects her character.