Time for true confession.  I'm looking for any band that you liked at a time when it wasn't "cool" to listen to them.  
 
For me, it's probably a lot of New Wave or synth-pop from the 80's.
 
A few to get started:  
My Daughter's Wedding--Their "big hit" was Lawnchairs.  I wouldn't be surprised if you haven't heard of them.  
 
Starbuck--Moonlight Feels Right.  I liked them for their synth-with-marimba-sound.  I've always liked the mallet instruments.  
 
Pablo Cruise--I liked several of their songs.  Somehow, I managed to avoid the over-exposure and didn't get burned out on them like on many songs that get over-played on radio.  I guess I wasn't listening to that station at that time.  
 
That's it for the moment.  I throw a few more more in later.  I hope you have fun thinking about it.  

Icehouse
 

 
Could never find anyone who liked 'em, I thought they were excellent. Iva Davies went on to have success as a film score composer ('Master & Commander'  etc)

Hey James, I like Icehouse!  In fact, Trojan Blue is on a CD I have of off-the-wall favorites.
 
Since I like a lot of genres, I could probably make a long list of bands, but I'll go with a favorite that many musician forums love to bash:  A Flock of Seagulls.

The Bangles - jangley guitars, nice harmonies and Susanna Hoffs' voice.

Old55
Time for true confession.  I'm looking for any band that you liked at a time when it wasn't "cool" to listen to them.  
 
 

I always seemed to pick stuff that wasn't cool. I remember walking in high school with a bunch of old Black Sabbath records and having the rest of the kids look at me as if I were the weirdest guy around. That's in the early/mid 80s when the 70s were absolutely not cool. 

Back then, even listening to KISS' Creatures of the Night was considered weird, because it dated back to their make up days - even if the album came out in late 82, just 2 or 3 years before.  For better or for worse, it was my favorite record for quite a while back then. Speaking of the aforementioned KISS, that's probably my biggest guilty pleasure...
 
Same thing when I discovered Led Zeppelin. Almost seems as if before the end of the 80s or the early 90s, 60s and 70s music was a big no go. It was our parents music... I was the only guy around playing trash metal wearing (home made) Beatles pins.
 
There are also specific albums that even fans of the artists seem to put down and which I enjoy. Alice Cooper's Lace and Whiskey and From the Inside come to mind, and everything from that period of his career. KISS Unmasked and even a few songs from The Elder. Stuff from Metallica's Load and Reload.
 
To be perfectly honest, guilty pleasures implies that one cares for other's opinions, and I don't. I'm kind of assuming by experience that some things aren't well seen by a certain kind of "serious" (frustrated) musicians. Like, you're not supposed to like The White Stripes, or Type O Negative or Stone Temple Pilots or Lenny Kravitz or Marilyn Manson or Cradle of Filth...
 
I like having self-proclaimed and wonderfully unknown real musicians getting all reeled up...
 
Oh - I'm a big fan of Oasis, too. :P
 
My guilty pleasure is to be able to hold my ground in a discussion with the people who put that stuff down. ;)

craigb
Hey James, I like Icehouse!  In fact, Trojan Blue is on a CD I have of off-the-wall favorites.
 

 
That's a good song!

This one by Sue Saad:
 
http://www.youtube.com/watch?v=8KKZL9wFvcw
 
 

One for Mosh...
 

 
Everyone I knew thought Chapman's voice was hilarious..

jamesg1213
One for Mosh...
 
Everyone I knew thought Chapman's voice was hilarious..

But the combination of that voice and that guitar in most work was outstanding! I just had a listen to the LP "Hyenas Only Laugh for Fun" and it is a very good album also.

I remember my friends giving me a hard time in the late eighties when I deviated from my usual heavy metal tendencies and started listening to a lot of Jimmy Reed. I can still hear him saying "ya betta get some inshowance on me baby".