When I need a little mood adjustment there's always one CD that I play. It never fails to lift my mood, even if just a little bit. My mom had this album (yes, a vinyl album) when I was in high school. Then when I was in college, one of my roommates owned it and would play it for me (Thanks, ooolia!) when I was feeling depressed (about a guy, of course!) No matter what kind of music you're into, this music will not fail to make you feel good.
So if you don't already have it, get your hands on a copy of Bolling Suite for Flute and Jazz Piano Trio, Jean-Pierre Rampal and Claude Bolling.