I don't exactly plan on looking through all of the pages to see if anyone else said this, but I know of some music that's great for writing.
Soundtracks from movies. Particularly soundtracks by Hans Zimmer! I highly suggest the Sherlock Holmes (2009) soundtrack.
Also, try music that's traditional in other countries! Middle-eastern music, such as music for Belly Dancing is good too. Not all instrumental music is like listening to Beethoven (Not that I don't enjoy classical music! But there are many people who don't.)
Hope this helps someone who may be looking for something new!