It's hard for me to decide my favs but I think the Zelda series takes the cake. Some of my favorite non-Zelda songs are Sticker Brush Symphony, Gormet Race, both Star Wolf songs, most of the Pokemon stuff, Ashleys Song, Chill - Dr. Mario, Luigi's Mansion Medley, MSG4 Theme of Love, His World, and of course, Sonic Boom. There are just so many good songs to choose from!
Also, if you want to fing a lot of stickers and CDs fast, go into stage builder and build a stage with conveyer (sp?) belts going into a wall. Add a ladder for second player so that he stays out of the way. Set items on high but only turn on sandbags. Once you start that match, just beat the snot out of all the sandbags untill they drop stuff. Since all items are off except for sandbags, all they drop are stickers or CDs! I'll try to post a screenshot of the stage I made to give you an idea.