to be honest i am quite happy with my 500gb, i am not playing all my games anyways all at the same time. I delete one if i am finished or not intending playing it for now.
A lot of japanese games arent taking so much space anyways and have view patches, same is true for indies so it depends what type of games you are playing. If you love AAA or Online only games mostly then yea get a bigger HDD.
You can always upgrade later with a 2TB internal HDD







