The little heap of snowballs on the right is too made up, it doesn't fit with the overall quality, too much cut and paste, you want to get rid of it :)
it is generally not very interesting. Maybe you'll want to add some colour in it, blue will work because its a cold colour. Also the snowballs are not working at all, just remove them because they don't add anything. Then finally try to think of the elements of your wallpaper (type and empty space) and make it so it's not just the type full screen in the center...
I'm thinking you might want to add some falling snow....and maybe tracks in the snow...and some variations in colours. But nothing too over-the-top or distracting. Also, the letters look a little too perfect, you might want to rough them up a bit. But these are all my personal opinions, I'm not exactly sure the look you are going for. Maybe adding other props to the scene (like a tree with no leaves covered in snow) is an option.
