i don't know for sure, never played, b i would hate to go int his order, greatest to least.
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Bach Aria from the Goldberg Variation
Chopin Raindrop Prelude no.15
Wagner The Liebestod
Beethoven Moonlight Sonatas
Debussy Clair De Lune
1) Bach's have 32nd note, trickier to master than a mere 8th.
2) Chopin's require stretching the hand, and playing a succession of 8th notes.
3) Wagner's left hand might be easier, but there are tricky parts.
4) Beethoven's repeat a lot i think. The trick is PROBABLY just knowing the scale, or what notes to play, it can even be played slow and it would sound good.
5) Debussy Clair De Lune holds the left hand.
Again i am not sure, i just looked at a page, so it might be misleading. General answer is that it depends on your level, what scales you know etc, how your fingers are and how far your hand stretch, how supple your wrist are (for chopin) etc.
i forgot to mention that Beethoven's music is more compacted.