I have "And Love Said No" by HIM stuck in my head. I saw them live last night and they played it, so it's not entirely unpleasant.
Back when I was in my high school orchestra, we played the Hallelujah Chorus at the Graduation ceremony every year. I'd get that same triplet stuck in my head all week, and by the time I realised it was out, it was time for the next orchestra rehersal, and I'd be stuck with it again.
Quick tip: It's know that Barry Manilow's?Copacabana? Will get rid of most earworms without lodging itself in. However that leaves you vulnerable to attack by another earworm such as this Latin America-only version of CARL!