I'm with Gris.
I like the unedited version of the third one, it seems more interesting. You upped the white on the clouds too much, and it dominates the picture. Something dominating the picture isn't bad, but in this case... it's all white clouds. And you can't really even see the difference in the clouds, it's just a giant swathe of white.
The first one would have been better if the glass had been clean.. :p I like the clouds, combined with their out-of-focusness (technical term right there, hell yeah.) it could have turned out well. You might want to try to
Second one is missing something. Again, like Gris said: It looks like it could have made an interesting picture through your eyes, but it didn't translate so well.
Third one is good though, I like that one a lot.
But MB is right too. I don't know if you can drive, or if someone else was driving you, but go find a nice spot with a good amount of diversity, and just walk around with your camera in your hands. The glass, even if it's almost unseeable like in the third one, makes the picture.. hrm. Hard to describe. Not boring, but less contrasty, and less alive.
But you've got some skill there. What kind of camera is it? Digital, I'm assuming. SLR?