I don't think I have any guilty pleasures whatsoever. This is because the only pop music I like is from before 2000 (even '96-'99 is something of a sparse wasteland) and anything I like from before 2000 is good enough in my opinion that I have zero reluctance for anyone to know I like it.
I still even catch myself listening to Ace of Base's album, the Bridge, at least once a year all the way through. Aside from that, I like the majority of top 40 from the 80s through the first half of '96. I know that sounds strangely specific but the middle of '96 involved a somewhat distinct transition from post-grunge and generally good early 90s style top 40 toward gimmicky fly-by-night ska bands and limp, lifeless acts like The Refreshments (they did the King of the Hill theme), Everclear, and others.
It just seemed like the top 40 was suddenly wiped clear of any new bands that were capable of making music that had any realistic passion or interesting facets to it. I think early '98 was possibly the final nail in the coffin for me. By then Matchbox 20 and Goo Goo Dolls were at their commercial peak and the rest of the Billboard spotlight was occupied by lightweights like Tonic, Third Eye Blind, Eve 6, Blink 182, and Semisonic, and not an ounce of balls, talent, or creativity was to be found in that barren soundscape as far as I was concerned.
Amidst all this were three diamonds in the rough for me, Days of the New, Creed, and Jimmie's Chicken Shack. DotN had one of the finest debut albums I've ever heard to this day (pure acoustic bliss with a brooding, bleak vibe that perfectly embodied what the stripped-down, earnest 90s were all about.) JCS' album, Pushing the Salmanilla Envelope is perfection through diversity in its truest form. For an album with 12 songs, I'd struggle to even lump any 5 of them together to convince someone it's the same artist (rock, funk, latin, Celtic, ska, and hard rock/metal are all represented.)
Lastly, people bash Creed a lot but the funny thing about that is, just like the Metallica haters who crawled out of the woodwork during the Napster debacle, most of Creed's haters were never even fans in the first place and piled on cuz it was the chic thing to do at the time and many never even knew anything from their debut besides My Own Prison and What's This Life For. Top to bottom that album is dripping with guitar work that ranges from melodic to metal to brilliantly soothing and/or uplifting. Just because Scott Stapp's a prima donna dick is no reason to ignore the excellence on display throughout the album.