"Mikrofonkåt" - September.
Probably the most recent addition to my chart. Ever since Petra Marklund's performance of this on that genuinely original Swedish TV format "Så mycket bättre" (series 1 line-up pictures above with September in the middle), I've loved her irresistibly catchy dance-pop version of this Petter song. And so does everyone else in Sweden - once it was commercially released, it shot up to the top of the iTunes chart and is still at no.1 as I write this.
This song (and TV show) have really boosted her profile again in her home country, just in time for her comeback single "Resuscitate Me" and forthcoming album "Love CPR". Maybe she'll be back in the 2011-50, one year from now!
That legendary TV appearance: http://www.youtube.com/watch?v=X4c2xI4WGVE