"Freddie's Dead" (Curtis Mayfield)

Even if you've never seen the 1972 blaxploitation film Super Fly, it's impossible to hear the gangsta lean congas, jazz flute, and rumbling bass of "Freddie's Dead" and not think of tricked out Cadillacs and 70s urban decay.
If you have seen the movie, you know the song is about the character "Fat Freddie," one of the few characters who dies in the film.  Freddie is kind of a pushover and screwup.  His main function in the plot is that he rats out the protagonist, "Youngblood Priest" (a.k.a. Superfly), to shady narcotics agents to save his own skin, only to be hit by a car as he attempts to flee the police precinct.
Being that Freddie is a relatively minor (and somewhat irritating) character, it always surprised me that Curtis Mayfield wrote what's essentially the movie's theme song about the guy.  But then I read this quote from Mayfield in the liner notes of the 1999 re-issue of the Super Fly soundtrack: "I had such a feeling for this character who wasn't really a bad man.  He just got caught up with the wrong people."
After reading that, it all made sense.  Nearly every song on Mayfield's soundtrack addresses the social ills and economic realities that led each character to a life of crime, and he takes extreme care to make sure you learn about the humanity of every individual.  In this case, the portrait he paints of Freddie is that of a man who was a victim of circumstance: a soft-hearted guy who was never cut out for dealing drugs or shaking people down for money.
So for every image on the big screen that glamorized the lifestyle (the cars, the clothes, the cash), there was Mayfield saying: hold up; what's the real cost of these things?  Remember, this man died because of these things.
It's a powerful message set to one of the catchiest grooves of the 70s.
And if you check out no other part of the song, take a listen to Joseph "Lucky" Scott's bassline on the breakdown around the 2:40 mark.  It's so funky, it hurts.

"Give Me Your Love" (Curtis Mayfield)

When Curtis Mayfield created the soundtrack for Super Fly (1972), he didn't just pull 9 songs from his back catalog or write some random stuff that was barely related to the film.  He took the time to read the entire script and wrote music and lyrics that commented specifically on the plot and inner workings of the characters' minds, exploring their hopes, doubts, and desires.
"Give Me Your Love" is written from the point of view of "Georgia," the steadfast girlfriend (played by Sheila Frazier) of the film's protagonist, "Priest" (played by Ron O'Neal).  In the film, "Priest" is looking to make one last, big drug deal and then plans to leave the business for good.  Whereas everyone else around him—from his cohorts to crooked cops—is trying to convince him to stay in the drug game, "Georgia" is the only one who really sees the toll it has taken on him and encourages him to leave it all behind.  The lyrics of the song express her unconditional love and her sole desire for "Priest" to succeed so they can be together.
"Give Me Your Love" underscores the (in)famous slow-motion scene where "Priest" and "Georgia" get freaky in a bubble bath, right after she implores him to stop shutting her out emotionally.  The track's undulating congas and insistent bassline provide a funky, Latin-tinged foundation for the lush strings, delicate piano, and Mayfield's falsetto vocals.  It's gritty and beautiful at the same time, which I think perfectly captures the relationship between the two characters.

"Superfly" (Curtis Mayfield)

Super Fly (the film) originally was released in mid-1972.  For better or worse, it set the stage for what came to be known as the "blaxploitation" genre.  
I've seen the film maybe twice over the years on late-night TV.  It's a story about "Youngblood Priest" (played by Ron O'Neal), a street-smart, young coke dealer who decides he wants out of the game, and all of the shady characters and crooked cops who try (by persuasion and/or violence) to keep him from making one last $1M score.
It's an okay film with decent performances.  But it's not really a movie you watch for the plot or the acting; you watch it to gawk at the crazy ass clothes and Priest's pimped-out, custom Cadillac (which, incidentally, belonged to an actual pimp named K.C., as the liner notes of the re-issued soundtrack album point out).
Speaking of the soundtrack, it's the most compelling reason to watch the film.
What makes it so good is that it's not two or three Mayfield songs, surrounded by a lot of cheesy instrumental filler; it's a complete Curtis Mayfield album.  He set out to create a work that would stand on its own while expressly tying each song to a scene or character in the film.  (Unfortunately, the editors of the film didn't always use the songs in the appropriate spots or to the greatest effect.  Key example: there's Mayfield's anti-drug song, "No Thing on Me," playing during a scene where Priest is convincing his old mentor to front him 30 kg of cocaine.)
In all cases, Mayfield never tried to glorify any of the situations depicted in the film; he simply was a omniscient narrator, chronicling what he observed, delving into the characters' thoughts, while constantly reminding the listener that these were human characters with human foibles.
Such is the case on the track "Superfly."  Mayfield more or less summarizes the entire plot of the film in the lyrics, characterizing Priest as a resourceful, complicated man who is the product of his environment.  As the song goes on, Mayfield comments that Priest realizes there's no future in dealing drugs, and although he has no clear idea of what the future holds or what challenges he's going to have to overcome to get there, he's still tryin' ta get over.
You can't beat Mayfield's singular voice on this tune.  But the stars of the show are the fat bass (played by Joseph "Lucky" Scott) and the pitch-sliding roto-toms and congas (by "Master" Henry Gibson) that punctuate the track.  It's no wonder why everyone from The Beasties to Sean Combs have sampled the intro hundreds of times.