Creating your own levels?
Playing the user-created levels?
Playing through the story mode?
Messing around with friends online?

So many things to do in LittleBigPlanet, I cannot wait. Personally I think I'll get the most fun out of playing user-created levels. I'm excited about being able to create my own levels, but I don't know how much patience I will have with it. Though I can see myself planning out different levels in my spare time, so maybe I'll use the create mode a lot more then I think.

How about everyone else?

What excites me the most is the ability to create my own levels. I love creating levels and other "stuff" in games that allow it and this game looks to be awesome...and being able to do that with buddies should be fun too. I will probably be "working" in the game more than actually playing it. :P

creating levels and have people playing and commenting on them

designing my own levels

well, mainly to play, create, and share. :D

Both creating and playing.
Cant wait to start messing around with the physics in making my own level will be awesome.

creation deffinetly

finding a way to recreate every level from Super Mario World in little big planet

Creating a level set inside a giant robot that slowly walks to the finish line
Throw in some traps and explosions inside so it will be kind of like an endurance level
Oh yeah
That is my goal

Probably being able to create your own level, have other people play it.

The fact that it isn't "just another platformer" like I've heard others say.  You can, as we've seen demonstrated, make literally ANYTHING.  I saw a video a long time ago showing how you could essentially make a fighting game with it.  You could even make a racing game.  What excites me is that every time it is shown there is something new, something we haven't seen before.  Also knowing that there are going to be so much new content uploaded by people around the world everyday!  Also after seeing what they did with it at E3 this year I really want to talk a teacher into letting me use it for a presentation at school. :D

The ability to make anything you want and to play with other friends on it. Sounds like a really cool game.

Level creation. Crazy use of physics.

"finding a way to recreate every level from Super Mario World in little big planet
"

i think what excites me the most is that my PS3 won't just sit there come october.

well iono, i guess when disgaea 3 comes around late august my PS3 will be constantly on.

but to stay on topic, i'm really interested in creating the levels. after seeing the E3 presentation (never really paid attention to gameplay videos before) i wanna make some fantastic levels.

no limits of what u can create

Dude it's fucking everything!!

The potential is just amazing, really.

The thing that excites me the most about LBP is the idea of a game thats built around user-generated content and the community experience.