I talked before about the trend of having shirtless men on romance covers, but another that I've noticed recently is the half-naked couple on the cover. I'm not talking about the bodice ripper historical covers -- those have been around forever and are still around. They have the wind-blown hair (going in more than one direction), the buttonless and open shirts, the gowns falling off of the heroines.
The new covers I'm talking about are much more modern looking. They look more like the covers I sometimes see on Black Lace or Blue Moon erotica. Some are historicals, but these new covers seem to be equally as common with contemporaries. These have a lot more class than the bodice rippers (though I still don't know that I would read them on the bus). The couple is often shadowed enough (like the Fetzer, the Clare, and the Moning" that the book doesn't scream "Hey, there's sex in this book!" It just says it politely.