Here are 3 opitions i've done..

1) http://img514.imageshack.us/my.php?image=parakissbluebgtexctbymepd6.jpg

2) http://img514.imageshack.us/my.php?image=parakisswallcn5.jpg

3) http://img89.imageshack.us/my.php?image=parakisswallbluems3.jpg

...in my opinion the purple one looks the best... but thats just me...
thats all the input i can give though... not exactly the best/most art-savy critic here...

I'm a bit confused

I've seen all three of them but every single of them has only a size of 600 x 450 px
I don't really know if this is the actual size you want to upload the wall with or if imageshack has cropped the image down (naturally imageshack does not do this).

OK, I just think that this is the size you want to upload your wall with.
If so, please read the guide.
Only wallpapers with minimum of 1024 x 768 px are accepted. Your's is way to small.

About the wall itself.
To be sure I don't like any of them. The pic of Yukari is nice but you need to work more on the background. I also don't really like the fact that the background is shining through Yukari's face. It looks a bit weird to me.

Also the wall looks really pixellated in some parts. You can best see this around the eyes of Yukari.

I think the user only shows a section of the wallpaper on purpose... not everyone wants to see it all ("spoiler" for the wallpaper). That was my impression.

Definitely the purple is the best. You take out the esence of Paradisse Kiss, with the style you give the picture. Good work!:)

I like number 3 the best, but I agree with angel-voice that the backgrounds could use more work and that the pixellation could be an issue.

The main critique I have to offer is that the walls are not very exciting. There's not much about them that grabs the eye and elicits an emotional reaction. It needs to be more stylized. Maybe you can think about what it is you're trying to say about Yukari with this wall. Are you showing her elegance and chic sensibility? Or maybe her strong personality in spite of her outward beauty?

My favorite part of the wall is the blended words across the top left background in number 3. And there's a cool paisley-like pattern going on very subtlely. I would love to see both of these expanded upon, like having the pattern be more visible and both pattern and words used across the whole outside background. I'm not a fan of the circle effects done across Yukari's face in the three walls, as they appear like weird tattoos. I would avoid using the circle effects entirely, since they are a little too geometric for the styling of the piece. You could also try highlighting some of her characteristics by making the brooch and/or scarf a different, contrasting color.

Good luck!

Angel voice is right.
First, the size. Submitting it as it is will get a rejection.
Second, there is pixelation on the girl, on all versions. The one on the hat -could- be ok, but it's on the hair, on the outlines, the eyes, everywhere. If the original scan is of that size I guess there's no hope of continuing that project... I'm sorry to say, but you should either have to vector that or just look for a scan of more quality to work with, specially if it's your first wall.
If you applied filters to make the girl look like it does, then maybe you should remove them...
The work with the texture and brushing is good on the second and third versions, but I insist, it must be bigger. Someone above said it's because you didn't want to "spoil" the wall, but if you want people to help you, you have to show all of it ^^U
I hope I can be of help...

Confusing ...

i think the best one for me is the first