"Smokestack Lightning" (Howlin' Wolf)

At some point, I went from being a Muddy Waters fanatic to a Howlin' Wolf fanatic.  Might have been around the time I got a Muddy Waters cassette stuck in the tape deck of my car in college, so every time I turned on the radio, there was always Muddy belting out "Hoochie Coochie Man," live from the Newport Jazz Festival, 1960.  Or maybe it was around age 20, when I bought a Chess Records compilation and heard Howlin' Wolf for the first time and was instantly mesmerized by that voice.  It sounded like liquor, buckshot, and razor blades, thrown in a blender on high speed.  
I loved it.  Still do.
But more than just the sound of Wolf's voice, there was a real earthiness and pain in his delivery.  Unlike Waters, Wolf's songs were less often about boasting or proving his virility and more often about being down on his luck in love: women cheated on him, left him, stole from him, and gave him gasoline instead of water when he was thirsty.  There's something inherently reassuring about a man of Olympic stature (he was 6'3" and nearly 300 pounds) who was as vulnerable as the rest of us mere mortals.
My all-time favorite bad luck song of his is the 1956 single "Smokestack Lightning"—a greasy recasting of his own 1951 song "Crying at Daybreak," which is a lament about his woman leaving him.  
In short, Wolf is watching a locomotive passing in the night, and he's wailing at the sight of the golden sparks coming out of the smokestack (i.e. "smokestack lightning"), knowing that his baby hopped that train and left him for good.  Or, to look at it another way: his woman found a flashy, new man willing to carry her.
Wolf's voice is mournful and haunting throughout the track.  I love his literal howls after each verse; they're as spine-tinglingly lupine as they are train-like.  Also, lead guitarist Hubert Sumlin's prototypical electric blues riff sounds as lonesome and lowdown as Wolf's moan itself.
In short, feeling this bad never sounded so damn good.

"Forty-four" (Howlin' Wolf)

Sometimes my affection for a song stems purely from how it sounds.  In fact, I'd say that most of this list consists of tracks that appeal to me sonically, often in the form of unusual arrangements, quirky time signatures, odd instrumentation, studio wizardry, etc.  That's not saying I don't listen to or consider lyrics; I love a thought-provoking, well-written lyric.  I simply mean that my musical pretensions aren't guided by a song having to say something.  If the words resonate with me, I just consider it an added bonus.
Anyway, that brings me to the song at hand: "Forty-four." This blues standard, which is either credited to blues/boogie pianist Roosevelt Sykes (who was the first to record it in 1929) or Sykes's mentor, pianist Lee Green, basically is about a madman roaming the streets with his .44 revolver, looking for his cheating wife.
A ballad it ain't.
For as creepy as Sykes's original is, though, the great Howlin' Wolf's 1954 version will make you want to lock your doors and windows and then check them twice.  
It begins with Otis Spann's barrelhouse piano, Earl Phillips's thunderous drum pattern (which sounds like an army on the march), and Hubert Sumlin's ugly, looking-for-trouble guitar riff.  After a few bars, Wolf's voice comes in, shouting/singing I wore my .44 so long / It done made my shoulder sore.  And, by God, I believe him.  No matter how many times I listen to this track, that moment sends chills up my spine, every time.
In all, the effect of the song is like some kind of late 1800s military field drill as recast by a South Side Chicago blues band after one too many shots of Wild Turkey.  It's loud, menacing, and sonically perfect in every way.

"Killing Floor" (Howlin' Wolf)

Based on the Depression-era song "Hard Time Killing Floor Blues" by Skip James (1931), "Killing Floor" (1964) is a track written/performed by Howlin' Wolf (a.k.a Chester Burnett) about being in a relationship where your mate has you so whipped and so down that you feel like you could die.  To convey just how beat he is, Wolf uses the metaphor of a "killing floor," i.e. the putrid slaughterhouse in a stockyard--a scene that probably would have been all too familiar to working class Chicagoans in the vicinity of 2120 South Michigan Ave.
(All of us have probably been in a similar situation at some point in our lives.  It's just a matter of whether or not we had the good sense to get the hell out!)
The brief but substantial song is driven by Wolf's signature growl and Hubert Sumlin's stinging electric lead guitar, which shreds through the song's signature riff.  
Led Zeppelin fans probably will recognize that riff as the basis of Led Zeppelin II's (1969) "The Lemon Song."  In fact, Burnett's music publisher, Arc Music, sued the band in 1972 for a co-writing credit on the song, ultimately settling out of court to the tune of $45K.

"Spoonful" (Howlin' Wolf)

Like a lot of Chester Burnett's (a.k.a. Howlin' Wolf's) output for Chess Records in the 1960s, "Spoonful" (1960) is a composition by writer/arranger/bassist Willie Dixon.  As the liner notes for Howlin' Wolf: The Definitive Collection (2007) state, Burnett himself had penned a number of hits in the 50s and wanted to keep writing and controlling his own output.  However, the owners of Chess Records (brothers Leonard and Phil Chess) saw to it that Dixon, who had a finger on pop tastes and a knack for crafting catchy riffs, was the only one writing new music for Wolf and labelmates like Muddy Waters to keep Chess competitive.  The liner notes from the album include a 60s-era quote from Burnett to music journalist Peter Guralnick: "I can do my own songs better, but, you see, they won't let me."

Even though he wasn't too thrilled about having to sing Dixon's songs (they got in shouting matches quite frequently), Burnett couldn't have asked for a song better suited to his gritty style than "Spoonful," which is loosely based on the recording "A Spoonful Blues" (1929) by Delta bluesman Charlie Patton.

The entire song rides atop a single chord and a shuffling groove as Burnett moans about lustful pursuits and the ends mankind will go to for a mere "spoonful*," his larger-than-life sandpaper baritone duetting perfectly with session guitarist Hubert Sumlin's confident, piercing lead. 
   

(*He ain't singing about a teaspoon, kids.)