"Dancing Days" (Led Zeppelin)

"Dancing Days" from Houses of the Holy (1973) is the perfect Zeppelin pop song.  It's a compact, rocking capsule of everything that made the band legendary: a thunderous (yet grooving) rhythm section, layers of exhilarating guitars, preternatural tenor vocals, and a fusion of East and West that blurs musical and geographical boundaries.

From all of the books, articles, and Web blurbs I've ingested and digested about the band since adolescence, I know the track was inspired by Jimmy Page and Robert Plant's travels in India, where the duo soaked up all of the music around them.  In short, the Indian rhythms and tunings they heard organically made their way into Page's undulating riff on "Dancing Days," which, incidentally, got its name because the band celebrated completing the song's backing track by dancing on the front lawn of Mick Jagger's mansion, Stargroves, where a good chunk of Houses of the Holy was recorded.

Lyrically, it's also one of my favorite Zeppelin songs.  Plant strikes a balance between cheeky innuendo ("tadpoles in jars" and whatnot) and bucolic fun, complete with booze-sipping at sunset.  In fact, this ode to summer does more for me than a dozen Tolkien references and ladies purchasing staircases into the clouds combined.

"D'yer Mak'er" (Led Zeppelin)

"D'yer Mak'er" from the 1973 album Houses of the Holy is probably one of the poppiest songs in Led Zeppelin's massive catalog.  But I wouldn't call it "lightweight" by any stretch of the imagination.  Sure, it doesn't blaze with leaden, electric blues fire like "Whole Lotta Love" or "Heartbreaker," but it's still a heavy groove, largely due to John Bonham's thunderous-yet-swinging drumming and John Paul Jones's insistent bassline.  What's more, Jimmy Page's understated riffing throughout, Jones's syncopated piano overdubs, and Robert Plant's pleading (almost vulnerable) delivery give it a certain sexiness that make it the ideal song for fogging up the windows of your hooptie with someone special.
Which is the perfect segue into talking about the title of the song.  It's pronounced "Jer-maker," not "Dire Maker," as people often think.  
It comes from the punchline of an old Cockney joke:
Man 1: My wife's going on 'oliday.
Man 2: D'yer mak 'er?  (As in, "Jamaica?" but spoken so fast and with Cockney r's inserted so that it comes out sounding like "Did you make her?")
Man 1: No, she's going on 'er own accord.
So it's a reference to "Jamaica," because the song is stylistically a take-off on dub reggae, as well as the phrase "Didja make 'er?" meaning...well, y'know.

"The Ocean" (Led Zeppelin)

I feel sorry for anyone who still thinks Led Zeppelin was a heavy metal band.  Classic Rock radio plays "Whole Lotta Love" 100 times a day, and people equate that with the band's entire output.  Even though that's like hearing only "Down By The Seaside" from Physical Graffiti and labeling them a country-rock outfit based on that one song.  
Sure, the boys could do blooze and decibels better than almost anyone out there in the 1970s.  But, heavy metal?  Hardly.
If anything, they had a strong affection for early, fun rock and roll--Little Richard, The Monotones, Jerry Lee Lewis, et al.  (I'll have to look this up, but I think maybe they even did a song about the subject.)  I think that influence is pretty apparent on Houses of the Holy's "The Ocean"--a tribute to their fans in which lyricist/lead vocalist/golden god Robert Plant likens the roaring sea of people at their concerts to an ocean.  
The whole song is done with a wink and smile.  There's John Bonham's barely audible chant at the beginning ("We done 4 [takes] already, but now we're steady, and then they went 1, 2, 3, 4...") before he and John Paul Jones trick you into thinking the song's in 4/4 before shifting to 7/8, just to fuck up your footwork.  There's Jimmy Page's little oooooh's on guitar that sound like a reenactment of a nubile groupie getting frisky with a mud shark.  And then there's Plant's a cappella lala-ing through the bridge, like he's about to teach us the letter of the day with Grover and Cookie Monster, just before everything abruptly shifts to a 50s-style doo-wop groove.
It's weird, wacky stuff.  And no one else could pull it off as gloriously and seamlessly as this band.