After the ranking of the hardest stages, it's time for something more unusual - list of most valuable stages - the ones, which are the best to buy. I think it could also be a nice guide for people, who downloaded the game recently, saved some diamonds/coins and don't know which song to buy.
Number one - Nutcracker op. 71. Probably the best stage to buy with coins, just because of its low cost - 5000 golden notes. Two-three days of collecting boxes. And in this price we get a very fast, hard piece with some double tiles. If somebody thinks, it's too hard for him - trust me, it's really good to train on very hard pieces. You won't be a very good player, if you won't put yourself in front of big challenges.
Number two - The Flight of the Bumblebee. 20000 coins seems to be a really serious amount of money, but I got it in almost one week (before the box update, with buying some notes with diamonds). This is one of the hardest stages in the game, but there is also another thing - in reality, this song is absurdly fast, and it is sometimes used to measure how fast pianists/guitarists are. It can be also a fun way to check how good are you in PT2.
Number three - Turkish March. I will just say that it costs 2000 coins and is the second longest stage in the game.
Number four - Waltz of the Flowers. It costs only 3000 coins, but offer a really big number of double tiles (even 14 in a row), but is really slow and can be a good way to learn playing doubles.
Number five - Csardas. With just 10 diamonds we can unlock a song with a crazy amount of double tiles - 3 times 24 doubles in a row! Small note - 24 double tiles in a row is a maximum, and can be found only in two stages - La Ronde des Lutins (one time) and Csardas (three times).
Number six - La Ronde des Lutins - as I said, you can find here 24 double tiles in a row, but it is also the second slowest stage in the game - starting with just 2.97 TPS. Great way to train double tiles, costs 5000 coins.
Number seven - Defend the Yellow River. Extremely fast and hard stage for advanced players, coming with price of 16 diamonds. Pretty expensive, yes, but remember, that pieces like Paganini Rhapsody var. 18 (Somewhere in Time) are much more expensive and don't check your skills like this one (actually, Paganini rhapsody sounds really nice, but I think its price is too high).
Nocturne op. 9 no. 1 and Sonata Pathetique Mvt. 3 - I know, they are the most expensive stages in the game, but if you were wondering if they are worth it - yes, they are. Fast, long, difficult and beautiful
and horribly expensive.
New World Symphony Mvt. 4 - just for the fans of Lord of The Rings.
The Tuileries Gardens - 12 diamonds for a really hard double tiles stage, I was really surprised when I found it. It's really not that easy to 3-crown it.
Romance de Amor - fine piece to test/improve your reflexes. It contains only holding tiles (blue ones) so it only challenges your eyes. 10 diamonds.
Clair de Lune - 1000+ stage, and it's really beautiful. Just for 16 diamonds.