In my kitchen we listen to my iPod on shuffle in the morning, turn it off, or very very low during service, and then switch to an internet radio station that plays "Deep and Soulful House" for our main prep hours between lunch and dinner. After that the night crew plugs in their music on a first-come-first-served basis.
My iPod has a little bit of everything; Slipknot, Michael Jackson, Trance, Dubstep, Celtic, Jazz, Offspring, Tupac, songs from Southpark, video game music... You get the picture.
Friday mornings start with my K-Pop playlist (currently 26 songs long).
I'm interested to know what stereo everyone is using. We're using a set of plug-in speakers with a subwoofer that our Saturday/Sunday prep-bot brought in after the nigh crew broke my iPod dock. You can connect USB or an Auxillary cable to the sub, which I'll admit is a splendid treat, after 8 years of low-quality ceiling speakers and cheap mini-stereos with no bass.