The thing is that wildlife and portraits have slightly different requirements, somewhat overlapping though. For the former you lots of mm, for the latter moderately long and wide aperture. The 70-200 f/2.8 has both but not to the extreme, and is expensive, the IS II even more. The f/4 versions are not as wide but less expensive. Choosing two different lenses is something to consider: a longer lens for the wildlife like the 70-300L that Dave suggested, or the 100-400L, and then a 85mm f/1.8 or 100 f/2 for portraits (and low light). You wouldn't have to spend all at once, but will spend more altogether, and get better lenses for the two purposes in return.
I went with the 85 f/1.8 and the 70-300L and am happy with both, but sometimes I wish I had the extra reach of the 100-400.
If portraiture is more important (you mentioned it first) I would start with the 85mm and save money towards a longer zoom. 200 is not very long, even on a crop camera.