Roger Davies was a popular, athletic Ravenclaw student at Hogwarts, a year or two older than Harry Potter. He was a Chaser on the Ravenclaw Quidditch Team, and Captain of the Team from 1993 to 1996 (at least).
Roger went with Fleur Delacour to the Yule Ball; he appeared to be so besotted with her that he could barely think. He missed his mouth with his fork when he tried to eat and babbled stupidly in response to what she said. Later, he and Fleur spent some romantic time in the rose garden outside (GF22, GF23).
Roger asked out Cho Chang in early February 1996, but she turned him down; Cho used the incident to try to make Harry jealous as they sat in Madam Puddifoot’s with Roger and his current girlfriend sitting at an adjacent table, kissing and cuddling (OP25, OP30).
A good-looking boy, popular with girls; good at Quidditch
Roger is a Germanic name meaning "famous spear" (hrod "fame" and ger "spear") (Behind the Name).
Although Davies is considered a Welsh surname, meaning "the son of David", it comes from the Hebrew דָּוִד Dawid "beloved". David (5th century) is the patron saint of Wales (Internet Surname Database).
While it's possible Roger is only a year older than Harry, it's more likely Roger is two years older. He is never mentioned after Harry's fifth year, and it's highly unlikely Fleur Delacour would have deigned to go to the Yule Ball with a fifteen-year-old; she considered Harry, at fourteen, to be a "little boy" (GF17). It would also be unusual for Davies to be Captain of the Ravenclaw Quidditch Team during the 1993-1994 school year if he were only a fourth year at the time; there has never been a Quidditch Captain in the series younger than fifth year.
Lexicon lists of:
From the Web
Pottermore feature: All about Ravenclaw
Harry Potter Wiki: Roger Davies