Cultural Rebel

A black person who loves hard rock and hates R&B? An Italian person who likes Mexican food just a little more than Italian food, even though he has not a drop of Mexican blood in him? A lifelong resident of Nashville who hates Country Music, preferring Heavy Metal—or, alternatively, Blues and Soul? A middle-aged adult who likes modern rock as well as classic rock? An American with a penchant for Canadian rock music? A blond teen girl who gets down with Death Metal and Gangsta Rap?

Basically, as much as many of us may argue that we are all individuals and have a right to our own preferences, there are still preferences that are stereotypically expected of us. As such, people who deviate from those expectations may face opposition (or, at least, odd looks) from other people — be it from people of their own cultural group or from outsiders. They may even be accused of cultural self-hatred, even if they have nothing against their cultural heritage, but see no reason why they should be limited to preferences within their own culture.

Perhaps, this character may not even start out as a rebel—but becomes rebellious only after repeated snide remarks about his preferences.

Examples of Cultural Rebel include:

Comic Books

In The Invisibles, Dane (a white English teenage guy) is a big fan of Gangsta Rap, and he asks Boy (a young African-American woman) whether she likes it. She says it's okay, but she prefers European techno. Later, we find out that her brother was an actual gangsta rapper.

Film

Buck Swope, Don Cheadle's character in Boogie Nights, is a fan of country/western music, to the point that he wears cowboy hats and shirts with fringes (the whole Roy Rogers getup). Remember, he's played by Don Cheadle
High School Musical has Zeke Baylor (a jock who bakes), Martha Cox (a nerd who likes Hip-hop dancing), and a skater boy who plays the cello, all during the song "Stick to the Status Quo". The first two become major supporting characters for the rest of the franchise while the last is never seen or mentioned again.
The Larry Clark movie Wassup Rockers follows a group of Latino kids in Los Angeles who follow punk and skater culture over hip-hop culture.

Literature

Holden of The Catcher in The Rye.
Yo-Less from the Johnny Maxwell Trilogy.

Live Action Television

The Big Bang Theory: Rajesh is not too fond of Indian food, while Howard takes a perverse thrill from not keeping kosher.
In Angel, Gunn doesn't start out this way. Then he sees a production of Giselle and falls in love with Ballet.
By Time Lord standards, the Doctor is this. They were staid, egotistical, and overly formal, not to mention were somewhat stagnant from a cultural standpoint. He, on the other hand, uses time travel to broaden his cultural perspective as far as possible, has (for the most part) no pretensions of being better than anyone else (aside from mentions of having Seen It All and his own genius, both of which tend to be quite true) simply because he was born a Time Lord, and he's so unorthodox and informal he (as well as his rival, The Master) is considered (from their point of view) the gold standard for a Time Lord Cloudcuckoolander.

Music

Eminem was arguably this for rap music, as he was the first white rapper to really break into mainstream respectability (sorry, Vanilla Ice).
The Runaways are a 1970s all-female hard rock band, and Joan Jett and Lita Ford have both made a breakaway success. It was quite rare at the time for women to perform hard rock (as opposed to soft rock or pop).
- From about the same time period was Pat Benatar. Then there was also Heart, but only the singers were female.
Dixie Peach is a black DJ who presented a soft rock show on BBC Radio 1 in the 1980s.
The whole Riot Grrrl movement could be seen as an example of this. After all, they are a group of feminists performing Punk Rock (a traditionally male-dominated genre).
Sinéad O'Connor, while her musical genre has always been strictly pop, has been the subject of controversy with her baldness—and she steadfastly refuses to let negative public opinion influence her decision.
Living Colour aren't really this trope because they are funky hard rock, but are commonly called metal.
Sepultura are a metal band from Brazil. Before them, the only music Brazil was known for on a widespread level was bossa nova. Thanks to Sepultura's influence, magazines started covering about metal from around the world rather than just the US, UK and Germany. Now we have the likes of death metal bands from India and Iran and power metal from Russia and Italy.
Many German metal bands formed out of a desire to make their country known for something apart from Schlager and Europop. They wanted to make it distinctive, and as a result German metal is heavier and scarier than anything else until Black Metal from Norway became famous a few years later.

Western Animation

Trixie Tang, the popular girl from The Fairly OddParents, is secretly a comic book fangirl.
- She also thinks dead frogs are "cool".
In ThunderCats (2011), Lion-O prefers researching technology (which most Thundercats scorn as a myth) to fighting and sees the Fantastic Racism of Cats being on top as wrong. Lampshaded at one point by his older brother, Tygra:

Tygra: You look at Lizards and see victims! You look at junk and see mythical tech!