The 90 (to me) is 90% portrait lens - the other 10% is when I need some telephoto assistance (ie, bird watching, nature, etc). I find it very limiting in everyday use as it is equivalent to 135mm in 35mm format which is pretty close up - most of the time I don't have room to walk backwards enough to get all I want in the photo - and then generally when I do get back far enough, there is something in the way that prevents me from getting just what I want in the picture. That said, it remains on my camera a lot more than most other lenses.
The 35mm lens (either 1.4 or 2.0) is a more general purpose lens. It is wide enough to get lots of territory into a frame. With the 35 one can get up close and lock in on a specific target (a face for example) or wide enough to shoot a landscape. In addition, either of the 35's are fast enough to shoot in low light - A very general, all-purpose lens!!
But I might suggest you also look into the 18-135 lens - while it is not particularly fast, I find it does a very good job - especially when traveling where one might be limited in changing lenses, yet, the environment might require fast changes for close up to very telephoto. This zoom can handle close up and far away with plume.