I do sometimes use the bright pink, but Fern's right, as long as you use the same colour all over the background, you can use any colour - I sometimes use bright blue or that greeny-blue, or white. :original: Black's a bit difficult as you can't see the edges of the creation very well.
I use the replace colour function of my paint program to make sure that I have not accidently darkened or lightened any pixels next to the object. :whistling The real thing that messes up the edges of creations is resizing or transforming them, when the program averages the colour of the edge pixels - you just have to use the clone tool on its smallest size to replace these and give a nice tidy edge.