Comic By Comic has a great post about celebing up the Marvel Universe. Check it out then return for my two cents.
I totallly agree with all of Rich's points, he's got the archetypes right and it's interesting that this really can't work on a total universe wide scale with DC like it could with marvel. Marvel comics has always had the aspect to its universe that there is a public at large and it may not fall in love with superheroes the way that they do in Metropolis.
The best example of using celbrity in superhero comics is Peter Milligan and Mike Allred's X-Statix. Which as I have said before is one of my favorite comic runs ever. This book really looks at the superhero life as more celebrity driven than heroic.
What no one ever talks about though is the celebrity associated with villainy. How would the world deal with some one like the Shocker or Rhino as a role model for troubled youth? Would Hank Pym go on the surreal life? Does America still root for Moon Knight after 9/11? Hasn't there also been some super hero story lines based around superhero paparazzi? Wow this post sucks I ended up rambling alot. Rich is a lot better than me.