Erykah Badu - Rimshot (Intro), Great bass (punchy and deep), Great 'klack' from drumstick hitting drum rim, Great Vocals.
Good test for muddy bass.
D' Angelo - Brown Sugar, Same as above but with added details, vocal effects, and intricate detail. Also listen to 'When We Get By' for some good jazzy instruments and stand out vocals.
Beastie Boys - Intergalactic, Lots of delicate effects that could get lost on lesser systems.
Bob Marley & The Wailers - Jamming, From the 'Legend' Album, Just perfect, vocals can sound 'compressed' and 'shut in' on lesser systems.