When I think ecchi anime I think more like Kanokon or To Love-Ru where they often give fan service, neither of which I like. I wouldn't really consider Onegai Sensei, Vandread, Da Capo, or Chobits as ecchi anime. They have their ecchi moments, but it's not like every action can be turned into fan service. And for the most part, it's not the main focus. For me, if it's a love comedy that seems to use those ecchi situations as the main theme, then it's an ecchi anime. In my experience action oriented animes tend not to be ecchi anime (although they contain ecchi moments). Of course there are exceptions like Tenjou Tenge, Grenadier, and Ikkitousen; but I tend not to watch those anyway.

And I usually dislike (my definition of) ecchi anime. Seeing the same jokes over and over gets boring. It would usually require a damn good story to make me overlook it. The only recent one that I can remember enjoying even a little is Strike Witches, as stupid as it is. This anime is pretty clear cut ecchi. Non pants wearing lolis combined with neko-mimi and getting up (non-existent) skirt points of view for random action scenes makes it ecchi.

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