I've played the first Pop'n Music! I had an imported version for the Dreamcast! ^.^ I've played the silly (and not very good) XBLA game 'Beat'n Groovy' too!
I really wish that I could play more Pop'n Music games, but there are no arcades anywhere any more where I live (not that they ever had a Pop'n Music machine anyway...), and importing Japanese PS2s and rhythm games are so rare and expensive!
I need my dose of Uncle Jam and... aaa... those two mascots... I forget their names. Nyami and Mimi, I think? The cat and rabbit! ^.^