Favorites have a tendency to sneak up a little. I listened to The Air Force a dozen or so times without thinking much of it. In fact, Xiu Xiu's fifth album didn't click for me until late one night after the wrecking crew across the street had long stopped loading broken buildings into a dumpster. So at 3 a.m., Jamie Stewart's video game symphony, his battered love letter, was finally backed by the proper blend of party people buzzing inaudibly, occasional horns, and my over-caffeinated twitching.

Considering Xiu Xiu's output, it's understandable you might overlook any number of releases: the covers EP, Tu Mi Piaci, is still fresh from the oven; the Grouper collaboration, Creepshow, is just around the corner; album six, with its much talked about Michael Gira duet, is bubbling on the horizon. Take a few breaths, though, and give these songs time to lodge themselves in your brain. The album floats perfectly from "Buzz Saw"'s opening piano (played by Deerhoof drummer Greg Saunier, who produced the record) through the quiet "walla walla walla walla walla walla hey" hook that tags the end of track six, "Bishop, CA". After that, koto instrumental "Saint Pedro Glue Stick" draws a line in the dirt, introducing the next act: torture, blood, suicide.

Largely focusing on love and death and what each means to individuals, the lyrics break from La Foret's angrier, war-torn metaphors to sharpened details of small yet catastrophic heartaches. On tie-me-up-and-runaway love song "Buzz Saw", Stewart's thoughts are as fragile and bare as nervous high-school nothings: "Your black hair is like black hair/ Mine I promise is a jerk's hair/ Your acne is like a pearl/ Mine I swear is brimstone." Goose bumps? Imperfection as gorgeousness: A chipped tooth, a scar, a leather belt around a wrist. The song unrolls like a hymn from beneath a bed, ending with a three-part, pitch-lapping harmony and bells-- exclamations that leave bruises.

Stewart said he penned the harrowing anthem "Boy Soprano" for a trio of younger men, between 18 and 22, who he knows on some level. It's a confusing mix of fascination, attraction, fear: "Look at me, nothing bad is ever/ Going to happen to you again/ Although you are a solid pile of hate/ You're still pretty like a cake." He's paternal, but isn't a father figure: The cake-pretty toughs don't trust him because he drinks "poncey" things like vodka and is well beyond the age that people would suspect him of lighting fires, as ascending notes and noise formations echo his increasing (sexual? emotional?) frustration.

"Hello From Eau Claire", Caralee McElroy first full-on Xiu Xiu front-woman gig, offers a bit of distance from Stewart's typical work. Xiu Xiu are great at gender-bending (see, for instance, "Sad Pony Guerrilla Girl"), so it's easy to think she's singing as a boy dreaming "that you might think of me as a man." When she lists her can-do's ("loose my own tie knot," "pay my own debts," "buy my own cigarettes," "pluck my own mustache," "rip off my own tights"), it's just as difficult to say: Girls wear ties; boys were tights; everyone has body hair, debts, and a desire for smokes. Regardless of how strong he/she thinks he/she might be, the strength crumbles in the final couplet: "I can humiliate myself to your face/ I can weep through my own midnights." Perhaps it's McElroy's vocals-- less dramatic than Stewart's-- but the song is the poppiest Xiu Xiu in memory. It's reminiscent of the Magnetic Fields before Stephin Merritt sang-- both because of the female vocal pattern, but also that tinny "100,000 Fireflies"-like synth.

And the love just keeps a-comin! "Vulture Piano" is among Stewart's catchiest hooks: He spells out the song title in full pitch-shift elf voice, before going into one of his "whoop, whoop" "I Luv the Valley, OH!" shouts. "PJ in the Streets..." is a tableau that references the Smiths' "Panic" and its "But Honey Pie, you're not safe here" sentiment.

"Saint Pedro Glue Stick" is that aforementioned, act-changing line in the sand. Sonically, it's a racket of Japanese koto (think: zither) and birds or human whistles. It's both boxy and spare; someone locked in a closet aviary. After it, violence becomes even more personal and intimate: Hands-on cutting and slicing. "The Pineapple vs. the Watermelon", a paeon to a father's suicide, is stripped down, thematically connected to the sounds before it: "The bird I am looking for is not in me/ It is you." A shift in vocal effects makes it sound as if Stewart's taking flight.

The Air Force closes with the one-man dialogue, "Wig Master". The instrumentation's simple: double bass, samples, and Stewart's pitch-shifting vocals. (The bass tone's amazing: a tea kettle half frozen.) Sounding childlike, Stewart speaks of a cactus bed and burning a lover's hair to stay warm, before switching back to his street voice to promise: "I'm gonna spank your ass so hard you will hate/ The wig master." "Wig Master"'s definition of loneliness: "Loneliness isn't being alone, it's when someone loves you/ And you don't have it in you to love them back." Finding fault in yourself for an inability to take advantage of a potential connection.

It's been a good year for the tortured. A couple of days ago I was scribbling my favorite 2006 albums on a napkin-- records by Scott Walker, Nachtmystium, Xasthur, the Knife, Junior Boys, and Tim Hecker, among others, creating a smeary Ian Curtis wish list. It made me wonder how Jamie Stewart feels about the turn toward a less smiley vibe. For a long time, it was de rigeur to label him the darkest, most fucked up guy in indie rock-- the dude that read Dennis Cooper and Mishima while listening to Morrissey and half-watching a documentary on hari-kari. That's romanticizing things, but Stewart's one of the more intriguingly dark, honest artists I've encountered across over the past few years. So hey, it's interesting then to note that just when the indie kids are switching their wardrobes to black, Xiu Xiu should unleash-- relatively speaking, of course-- their most understated, surprisingly sweetest album to date.