Whilst the 70-200 f/2.8 v2 is a magical lens on full frame, somehow, as someone else mentioned, it doesn't really gel on a crop body.
This is my experience exactly. I shoot with the 7D and out of all my lenses the 70-200 is the least used. As said before it is either too long inside or too short outside (really awkward to use); however, when the focal length is just right it is a magical lens. The ONLY reason I haven't sold it is because I intend to to upgrade to FF relatively soon...but for the time being it mostly stays at home in its protective case.
In my experience, my first lens was the 18-135 (non STM). This was a good lens, but I did see a very noticeable improvement in IQ when I upgraded it to the 15-85. The 15-85 is my most used lens for everything but birding. The 50 1.8 as cheap as it is is great for low light photography. And the 100-400 is pretty good for birding.
so my recommendation would be a 15-85 for general photography (people, places, and things) and if you want to take your wildlife photography to the next level look at the 100-400 or the 400 5.6.