A certain administration which I won't call by name took the arts out of the schools, and that left the brothers out on the street with nothing, so they went to the turntables and started rhyming. Then they had a way to express themselves, and that's the birth of hip-hop.
Old school hip hop comprised four ingredients—graffiti, DJ-ing, MC-ing, and beat boxing (Breakdancing is another staple, but not within the context of hip hop music, just hip hop culture). Nowadays, it is often viewed as 'another name for rap'.
Back in the days of old school rap, hip hop was often used as part of someone who is Totally Radical. With the rise of popularity of the far more aggressive gangsta rap, and hardcore Hip-hop rap is now used as a motif for anything related to the darker aspects of street life. If you hear hip hop in the soundtrack, you can be sure that everything is taking place on the wrong side of the law.
Note that there are many different scenes, subgenres, and cultures within hip hop besides gangsta rap. Even gangsta rap has several sub-forms like Horrorcore, and Mafioso rap. Unfortunately, they rarely receive anywhere near the attention in other media (or anywhere near the record sales).
'Conscious' hip hop artists such as Mos Def, A Tribe Called Quest, or even Common, may be used in a soundtrack to give an urban yet indie feel.
The Fast and the Furious series runneth over with this kind of motif. Even the third movie which takes place in Japan (I WONDAA IF YOO KNO HOW THEY RIIBU IN TO-KY-O!!! IF YOO SIIN IT AND YOU FEERIIT DEN YOO KNO YOO HABU TOO GO! FAST AND FURIUUUUUS!!!)
Grand Theft Auto: San Andreas also plays this one; although you can listen to any kind of music in the radio (although you a busta if you do,) most of the music featured in the cutscenes is gangsta rap.
The delinquent hotrods in Cars are introduced blasting hip-hop from their speakers.
Pretty much completely averted in Skins when Cassie's kindly middle-aged driver starts blasting "Move, Bitch" by Ludacris.
The background character Posh Kenneth pretty much exists solely to take the piss out of this trope.
And referenced in a crazy Crowning Moment of Funny in JJ's S4 episode when he and his equally nice mum are in a ludicrously cute 2CV singing along to "Vicks", "My Hooker" and "White Ladies" (written for the show by Fat Segal and Daniel Kaluuya - the bloke who played Posh Kenneth - but you can probably guess what they sound like from the titles).
Unsurprisingly all over the Def Jam Series since it was licensed by the record company of the same name and featured many Hip Hop and Rap artists as fighters.
The announcement that MadWorld would have an entirely hip-hop/rap soundtrack surprised the hell out of many people. Then the game came out.
The gangster controlling the block in Attack the Block produces his own Gangsta Rap, which shows off how much he's romanticised his own image of being a gangster. The other character in the movie shown prominently listening to hip-hop is the wealthy white college student who goes to the block to buy weed from the gang members, whose taste in music combined with his clueless contribution to the social conditions that produced all the music he likes is used for deliberate irony.
Confirmation Bias / Don't Shoot the Message: A lot of people, casual listeners and purists alike, tend to love or hate hip hop (and its subgenres) based on its messages, imagery, and other factors more so than the actual music itself.
Controversy Proof Image: Exceptions being Ice-T's cop killer controversy, which for all intents and purposes ruined his mainstream career as a rappernote Even though the Body Count album was Heavy Metal, not rap and Nelly, due to the tip drill controversy. Possibly Public Enemy as well thanks to Professor Grif's comments about Jews.
Cool Car: Exotic cars , low-riders and modded car culture in general has always been a huge part of hip-hop culture.
Stronger radio and video censorship towards Hardcore Hip Hop, Gangsta Rap, and Political Rap. MTV even refused to play a certain Public Enemy video because of a political statement. This become an extreme wall banger when you realized how the sexually explicit videos were rarely if ever banned, but violence and political statements were apparently where they drew the line.
Some even say West Coast hip-hop specifically was blacklisted because of the East Coast/West Coast rivalries, and because of this it never recovered. Then there was the death of 2pac and the collapse of Death Row Records and its rivalRuthless Records thanks to Executive Meddling (according to Bone Thugs-n-Harmony). After that West Coast rap in general, gangsta or otherwise, was persona non grata.
Conscious Hip Hop, likely due to the Afrocentric overtones not being broadlyappealing. The beginning of the end was probably when the mainstream ignored Digable Planets's more Afrocentric album Blowout Comb, and Arrested Development's follow up album Zingalamaduni.
Enemies Equals Greatness: A lot of rap songs are all over this trope, especially songs from the Glam Rap and Swag Rap sub-genres. Just about every rapper loves to talk about their "haters" in their lyrics.
Murder Simulators: Rap music has been a popular scapegoat for almost 20 years. The media frenzy died down around the mid 90's, then in '99, Eminem made his debut and the controversy went right back into full swing. People often blame it (and video games) for teens' insensitivity to violence and for promoting stereotypes about women.
Token Minority: Female and/or non-black rappers, at least in North America. In countries where Africans are non-existent or a tiny minority, the majority of rappers will be whatever is most prevalent.
Interestingly enough for most of The Nineties female emcees was quite common. So much so that arguably they wouldn't count as a Token Minority. But after the turn of the millennium all that changed. This has been brought up in a lot of Hip Hop mags and blogs.
Female rap does seem to be entering something of a renaissance as of the early 2010s, though.
In Australia, talents like Diafrix, 1/6 and N'fa (who worked with Heath Ledger, believe it or not) head the very small number of African-Australian emcees. Indigenous hip-hop is another significant minority subculture.