Funki Porcini–Love, Pussycats, and Carwrecks
Erm, the last time I remember having any sort of music on during sex was when my boyfriend and I were testing out some of the tracks from the House of 1000 Corpses soundtrack. Off of that, I’d recommend most of the original songs written and performed by Rob Zombie from that album. 
That was a fun afternoon!
Ravel’s Bolero.
Prince has some groovy stuff that really works for gettin’ it on… if you like funk.
I would also highly suggest Jeff Buckley’s version of “Hallelujah” off his CD, Grace, as well as, “Lilac Wine”, “Lover, You Should’ve Come Over”, and “Corpus Christi” from the same CD. VERY ROMANTIC STUFF!! Jeff Buckley had the voice of an angel, truly (we miss you, Jeff!).
Another good one for lovemakin’ is a song I can’t remember the name of but it’s on the soundtrack to “Bladerunner”, it’s an instrumental song with saxophone that is slow and SEXY! Kind of dreamy, too. That just totally seduces me sigh, honest to God, you NEED that song!
Bleh… forgot to mention most anything by Dead Can Dance!! Celtic/Hindu mix of truly original music that’s dreamy, exotic, and beautiful. Romantic stuff.
Bonus points if you can actually last until the end of this.
Stuff by Enigma works well for me. Preferrably with either auto repeat on or with several disks on the player.
When things are getting a little urgent, just think of the fat conductor bloke in Allegro Non Troppo and that will cool things down for you.
Oh, yeah. Dead Can Dance is great action music.
My personal fave though is the William Tell Overture. Nice slow build-up, then frenzied climax.
Santana, Matchbox 20…standards.
For especially chilled out sex, Cafe del Mar is pretty interesting.
For slightly more down’n’dirty sex, the music from the Matrix 2 ‘rave in the cave’ scene is rather inspiring 
I recently made up an entire CD for this purpose.
It’s stuck in a CD player at a friends house right now (I mean REALLY stuck, damn CD player). The tracks I remember putting on there that worked best (for me) were “I Want A Little Sugar In My Bowl” (Nina Simone), “Sweet Harmony” (The Beloved), “Breakfast In Bed” (UB40), “How Soon Is Now” (The Smiths), “I Want Your Hands On Me” (Sinead O’Connor), “Closer” (Nine Inch Nails), and “Pour Some Sugar On Me” (Def Leppard).
“Closer” is best for wall-to-wall, shake-the-chandeliers sex (and if fucking ever had a national anthem, this would be it). Nina Simone’s husky voice is great in many of her songs and always gets me going.
Synth world music like that from Deep Forest, Enigma, and Enya is also great foreplay and rhythmic sex music.
Like SanguineSpider said, smoky lounge songs with plenty of sax are great for getting in the mood. And I know that song from Bladerunner you’re talking about, I love it!
There’s a Canadian band called Godspeed You Black Emperor! who put out an album called Lift Your Skinny Fists Like Antennas To Heaven. I’d never heard it until the GF played during an intimate evening, and I was completely amazed.
There are some samples on the Amazon page there, but they’re only about 30 seconds long and aren’t at all representative of the music. The songs are instrumental and tend to be in the 20-30 minute range, and they start out very small, and they build, and build, and build, and build some more, and then when you think they can’t possibly build any more they go find a brand-new direction to build in, and so on and so on. It’s really amazing stuff, heartily recommended for those “special occasions.”
“Whip It”
“Beat It”
“Turning Japanese”
“Dancing With Myself”
“Born to Hand Jive”
The entire After Bathing at Baxter’s CD by Jefferson Airplane is a good place to start.
Followed by a whinny-ing horse.
Shirley
Who was that Masked Man?
Horseflesh, that song can also make me cry if I’m feeling lonely. I wish I had that soundtrack right now… that’s just the sexiest damn song ever!!!
Do you happen to know the name of the song, Horseflesh? Is it “Rachel’s Song” or “Love Theme”? That whole soundtrack is really good regardless.
Headin’ for the south lands, lookin’ for some fun
Down below that dixie mason I know you’re the one
My tongue is chasin’ my eyes are wide, I can see paradise
I been down here once or twice but I never seen it look so nice
ahhhhhhhhh yeahhhh
ahhhhhhhhh yeah yeah
I like it with the grass cut low
Big mountain tops valley below
I love it when you scream out my name
- Kid Rock -
Rock and roll chick signing in.
Sex on Wheels
My Life wth the Thrill Kill Cult
Ohhhhh, yeaaahhhh.
Normally: 311 or Radiohead
Severance Sex: Anything by the olsen twins.