For me:
Kate Bush-Sensual World
Jeff Buckley-Lover, You Should’ve Come Over
Rilo Kiley-Portions For Foxes
…And You Will Know Us By The Trail of Dead-Another Morning Stoner (thanks, Skewbald!)
TV On The Radio-Wolf Like Me
Stone Roses-I Wanna Be Adored
Prince-Little Red Corvette, I Wonder U, Adore, If I Was Your Girlfriend, Come, etc,etc,etc.
and 23 others that I can’t think of at the moment
You?
Well, everything by Prince to start with (I wanna melt with u, let’s pretend we’re married, black sweat, damn u, the greatest romance ever sold, do me baby, jack u off, ripopgodazippa, freaks on this side, hot wit u, and god created woman, tell me how u want 2 be done…)
“Insatiable” by Darren Hayes
“You’re Making Me High” by Toni Braxton
“Don’t Let Go (Love)” by En Vogue
“Crazy On You” by Heart
“I Was Made For Loving You” by Kiss
Just about every song on the Flirt soundtrack gets me hot and bothered.
Totally cheesy but Journeys “lovin’ touchin’ squeezin” prompted me to call my girlfriend in high school and re kindle a relationship, which was more less doomed anyway. we broke up again a month later.
“Dogs of Lust”, The The
Ravel’s “Bolero” raises my thoughts of Bo Derek in “10”, among other things. It goes with the flow.
I second “Crazy on You” by Heart. That song is like pure sex.
Also, White Stripes´ “Dead Leaves on the Dirty Ground.”
And Madonna´s… well, Madonna.
At long last, someone else who knows this song! And I definitely agree.
“Sexual Healing” by Marvin Gaye will put me in the mood every time, without fail.
For me, it’s Peter Gabriel’s “Signal to Noise” off the “Up” CD. That thing builds to a crescendo that’s positively orgasmic.
Also, anything industrial with a very strong beat. Industrial music is sexy.
I looooove to sing with this song. He sings right in my range!
“Sexual Healing” - what about “Let’s Get it On?” Too obvious? 
Heh. Yup, I guess I like my make-out songs to be a leetle bit more coy.
Al Green, Let’s Stay Together. Who croons better than the Reverend Al?
Paul McCartney, Maybe I’m Amazed. Total love and devotion for the subject of the song. For sure *I’m * amazed!
KC & the Sunshine Band, Get Down Tonight. (history involved)
Rick James, Super Freak. (history again)
Marvin Gaye, Let’s Get It On. Yeah, okay! Who could say no? His death (aside from being a bizarre fucked-up tragedy) ruined a thousand technicolor fantasies.
And, at the risk of sounding like a DMB one trick pony (yes, I’m a fan–so shoot me), Dave Matthews Band, Crush
Sinead O’Connor’s version of “Curly Locks”. That’s a great one.
How about the cover of Sexual Healing by Darren Hayes? Theres a song to make out to!
Ooooooo, there is one? I have to look for that, thanks!
30 years later and I Go Crazy by Paul Davis still makes me want to grab someone and make out.
Wicked Games by Chris Isaac is very sensual, too.