I sometimes take a casein shake before bed, although an omelette 90mins pre-bed is another favourite of mine.
I used to take whey pre and post-WO, but now I just do a solid meal, and I only do a shake PWO if I don't have time to eat right away, or if I want to do a bit of cardio PWO. Isolate is purer, but also pricier and I only recommend it if you can't tolerate whey concentrate. That being said some people are concerned about super-fast absorption, and for that I'd recommend EAA's/BCAA's sipped during your workout if you're really concerned about that.