The big question: is 4GB of ram enough?

I'm a college student and looking for a laptop. I have a google chromebook, but have enough money saved to to buy a rMBP. I want the newest model, but the base model only has 4GB of ram, unfortunately. I will not be running intense programs. Mostly word documents, excel spreadsheets, doing research on the web, and iTunes. I have an iMac at home as my primary computer. I just need something portable for school (the Chromebook is not cutting in anymore).

OR

I can get last year's rMBP for $1160 refurbished on Apple's site that comes with 8GB or ram. I do not want to spend over $1,400.

So, which option would you advise me choosing? I also will be doing some light photo editing, but nothing too big (I have my iMac for that).