Tech Advice for a New Philosophy Grad Student

Readers, please share what has worked well for you (and perhaps what hasn’t). Thank you!
I am entering a PhD program this fall. I am starting to plan and organize for this challenge. This includes considering buying a tablet (Ipad or Surface Pro). I currently write all my notes on paper. I hope to change to electronic note taking because of the organizational benefits and environmental impact… What do professors and/or PhD students use to organize their research? Is it possible to go through a doctoral program with just a tablet? Furthermore, and perhaps most importantly, what apps do people use to annotate papers and write/store their notes? 

He writes:
A student who will be entering a philosophy PhD program in the fall is seeking advice about hardware and software for his studies.