Easily Super Paper Mario. The original is my favorite game of all time and the second one is in my top ten. Super Paper Mario took out a lot of great stuff from the original two and didn't really seem like much of a game.

This is like asking which is the worst ferrari.

Gotta go with Super Paper Mario. It was a pretty enjoyable game, but it was just missing too much of what I had come to love about the other two games. I wish we'd get a proper sequel on the Wii.

Paper Mario is no Super Mario RPG even though I love me some kooper, but Geno, Peach,  Bowser, and Mallow had so much more depth than Bomb Betty, Goombario, and the rest of the cast.

My vote goes to SPM for this poll.

Ugh, I hated all three of these games. It's like choosing which is the worst douchebag, or worst turd sandwich (kudos to whoever gets the references)

I hated Super Paper Mario, from what I played of the others they were alright.

All were very good, but I do think Super Paper Mario was the worst. One of my problems with it is that because you could keep building your characters up at certain places, which I did like, but as a result it made the combat become too easy because I was definitely overpowered. Also, it didn't have much replay value. I considered buying it but ended up beating it after my 2nd rental and didn't see any reason to buy it at that point.

Where does Super Mario RPG fit on the scale?

Super Paper Mario was no where near as enjoyable as the first two.

Everyone who voted for Paper Mario and the Thousand Year Door is going to die a horrible, painful death.
 
The answer is obviously Super Paper Mario.