I LOVE Cm! A l;ot of my piano music (but not guitar music) is in Cm. I love the way the keys are lined up in Cm, which seem to faciltate a seamless transition to Eb, Ab, Bb, or even Fm.
(I know this is possible in every key, but there is something about Cm that makes composition in that key very easy and fun for me.)
Beethoven practically slapped a copyright on C minor.