The obligatory panty-shot, the character who is there just to have big breasts, and the classic "walking in on someone changing/showering" scene. Loads of anime use them constantly.
I feel like fan-service is sometimes used a cheep filler. There are some well-written shows that can use sexuality well, and tie it in with the overall feeling of the anime. The angles and imagery in Bakemonogatari, for example, do well with portraying how a character feels or how they are seen through the eyes of another. Then I look at Highschool of the Dead, and see a show with a really good story and well-written characters, flooded with jiggling body-parts.
As a man, I can't say I don't enjoy a good bouncing breast now and again. Yet, I sometimes feel that they just throw a pair of boobs or a panty-shot at me just to appeal to me with sex. Which isn't as interesting to me as a very well put together and thought out plot.
However, this is just my opinion, and I am wondering what anyone else thinks about this.