The Simpsons has been on for a really long time. The cartoon is still pretty funny, if you like animation. I like Homer the best, though Apu is a favorite too. If you really like the Simpsons and want to decorate your iPhone with a Homer sticker, I have the thing for you.
Over on Etsy you can pick up a sticker for the back of your iPhone that shows Homer getting smacked in the head with the Apple logo on your iPhone. The sticker is shown on the iPhone 3GS and shows up better on the black phone.
That said there is no reason this won't fit on the original iPhone or the new iPhone 4 as well. This would be a great thing for your iPhone 4 if you use the bumper case to show it off. You can pick the sticker up for $9.90 and three are left. That does seem a bit expensive for a sticker.