Probably close to half of the music that I love and listen is shit that a lot of people would consider "guilty pleasure" music.
My formative music years (when I wasn't listening to my dad's old classic rock albums or my mom's Beatles tapes) were spent watching a lot of MTV during the peak era of Britney Spears, Backstreet Boys, and *NSYNC. And I've always felt that that's informed some of my tastes to this day. I'm talking '98 - '01 here.
Also, my username on this message board sort of gives me up right off the top. Girls Aloud are just about my favorite thing to ever happen to pop music, and they are a super cheesy, crazy campy, "guilty pleasure" act. Fuck it. Life's too short.
The rest of the list of "guilty pleasure" artists that I dig is too long to list here. But I guess I'll list some of the bigger names that come to mind:
Miley Cyrus (I legitimately, no bullshit, love her tunes)
Ashlee Simpson (All three of her albums to date are dope)
Carrie Underwood
Avril Lavigne
The aforementioned Britney, Backstreet, and NSYNC
Kelly Clarkson
And, of course, as I think most of the people on this forum know...easily my favorite musician right now is a young woman who 98% of the population of twenty-something males in the world wouldn't be caught dead admitting they like. Fuck it. Cross the plane. I put the team on my back. Her songs make me happy, and they comfort me, and I think she's an absolutely fucking brilliant genius songwriter. And her name is Taylor Swift.