As long as it's not too obnoxious, I don't mind it all that much... consider Crazy Taxi. That had real locations like KFC in it, and it gave a certain sense of realism to the city. (Not the gameplay, of course, which is still as far from realistic as you can get.)
Not a bad article, djp. I remember owning a Kool-Aid Man game for the Atari waaaaay back in the day... hasn't really influenced my consumer habits much, though.
