As a relatively new fan I know only popular songs of AKB48, so for me it's always pleasure to find new gems.
Right now I have "Jun'ai no Crescendo" on repeat. I think I heard it first at Mariko's last theatre stage. I immediately loved it that time, though it wasn't performed by original No sleeves girls. then I was very lucky to see them live (no3b) at Sapporo Dome. and it was sooo great

it's a shame if they don't include it on DVD.
after the concert I forgot about the song a bit, but now I finally downloaded it and just can't stop listening!