Shepard Fairey created probably the most recognizable U.S. street art with his "Obey the Giant" series. He has come under some scrutiny for his oeuvre's liberally borrowing (and profiting) from the intellectual property of others. The NY Times runs an interesting article about Fairey's iconic image from 2008's election based upon an AP photo. It's a good read.
How soon before we have his "Obey the Obama" series plastered all over town at every fwy on-ramp, construction site, and/or bus stop? Say it with me, "Obey the Obama ... Obey the Obama."