As a 3d modeler I’d say in the long run it doesn’t really matter. Maybe 10 years ago it would but now with all the updates/new versions/new tools it really doesn’t. That said I’m using Maya and can’t recomend it enough. It’s a huge program with tons of features and chances are you are never going to learn 100% of Maya’s abilities.
Maya LT is really good for starters but keep in mind you’re not going to be able to release paid content with it.
As for learning now, DT is good for beginners. When you feel quite confident I’d suggest you switch over to Gnomon Workshop (it’s pay per dvd last I checked). Another good site is Simplymaya.
For texturing I went the Photoshop road and I’m using Crazybumb or Quixel NDo2 (both free) for generating normals (and other kinds of maps based on a picture). Allegorithmic’s Substance is really good as suggested but it’s a bit overwhelming for beginners.
And once you find how to manage materials/shaders from Maya to UE4 in order to achieve a photorealistic result, I’d really like to know, or even better if you find a good tutorial for it 