We've all been there, and that's why I'm here, writing this post. Music gets me through those times. With the right type of music you, like my frail, soon-to-be-dead iPod and I, can endure. My recommendations below.
"1812 Overture" Pandora station. Why? because my fifth grade teacher told me classical music makes you smarter, and it fades to the background nicely. Sometimes though it gets interesting and you some real soundtrack type jams going on. Ideal for the last page of your ten-page paper, makes finishing it feel far more epic.
Aphex Twin - Selected Ambient Works 85-92 Aphex's beats were completely revolutionary at the time, but now the sounds are somewhat commonplace in music, making this album interesting, but not distractingly so. This early electronica collection is makes a good base layer to build your consciousness off of as you ignore the prick two cubicles in front of you who believes Stacks is the best place to call his mom.
Anything by Pretty Lights This DJ's sounds really are perhaps best described by his name. Like a pretty light, this music is enjoyable to listen to but doesn't really have anything artistic in it to distract you. It uses minimal amounts of vocals, like most turntablist DJ's, but it's not quite as engrossing as say RJD2 in his Deadringer days and makes for great study sounds.
Anything by Ratatat Unlike all the other ideas I've thrown up so far, I actually listen to Ratatat outside of a study setting. Their music is almost too head-nod-inducing to put on this list, but I've listened to their stuff enough that it doesn't distract me too much. And it's all completely a capella (skip the Remix mixtapes for your studies).
Shine Blockas - Big Boi ft. Gucci Mane This is actually not a study song. This is just something I listen to when I'm tired of studying and I need a morale boost. This is off the forever delayed Sir Luscious Left Foot and was undeniably one of the best hip-hop songs from '09; I still can't stop listening to it.
I'd also throw in any music you know really well. Vocals can be distracting, but if you know them well enough they're more easily faded to the background.