The stickers bug the heck out of me so I always remove them. Last year when my mom got a new laptop and wanted me to help her set it up, I just about went crazy when I saw all the stickers on it. I started to remove them, and then she got upset. She actually LIKES them on there. Can't understand it, but I'm guessing she just likes colorful things.
As for getting them off cleanly without residue, grab a lighter. I always keep a Bic lighter with my tools for things like this. Just pass the flame around the sticker a few times to heat up the glue. It won't burn or damage the surface underneath unless you just let it sit there, so keep it moving. After about 30 seconds or so, go to peel the sticker up. The heating the glue softens its bond and it usually pulls up cleanly. I suppose you could also use heatgun for this if you have one, but I don't so I can't say for sure.
-Jeff