I game a lot on mine (Far Cry 3, Alien Isolation, Bioshock infinite... I've never seen more than 8-10GB of RAM occupied under my Windows session...
You need more than 16GB if you are editing HD/4k videos or very huge photos, if you use virtual machines... But for internet, gaming, casual photo editing, 16GB is enough.
Just think that if you buy 2x4GB, the day you will need more RAM, you will need to sell one pair of 4GB modules...
Okay great, I'm about to buy this. Is this the best value for money or is there something cheaper with similar performance. http://eshop.macsales.com/item/Other World Computing/1867DDR3S08S/
I really appreciate the help.