(Ok Ok, it is really a 5 star situation as far as I'm concerned, but I wanted to leave room for New Jersey and Keep the Faith)
Yes, this is a "classic." Though not the musical muscle flex of their later works (you MUST go endure my ranting review of the Blaze of Glory Album if you haven't already), Slippery When Wet not only 1) generated the mass hits that for many people are the only Bon Jovi songs they know, 2)saved Bon Jovi's career and ALLOWED them to make better albums later on, 3) defined an era, and 4) unified a "band sound" for them, but it was the embryo of what would become the most profound emotional journey as the band marched onward to later albums. This is an essential album both for the band to have made, and for anyone's collection. I don't care how many copies it sells (though please go by another copy so we can see the thing push another platinum level), it's not as good as Jersey, Blaze of Glory (the Holy Grail), or Faith, ... but it IS good, and when in the right mood, it can still serve emotional functions even after having been listened to for a decade and a half. If you don't have it, would you please just go get it? Enough said about Slippery, as the music speaks for itself.