Nick and I recently bought a pop'n stage ex cabinet to add to our growing little collection of music game machines. I've played it several times in the past but now that I have one all to myself, I'm absolutely in love with it. Really well thought out charts, all of the music is great (pop'n 3 vs. pop'n stage is still one of my favorite OSTS), and it has all of the Little Cure songs that were ever in the series (including COOL DANCE which was never on anything else).
pop'n stage ex - a set on Flickr
I really wish Konami would have kept going with the concept. So freaking good.