Do I need to buy extra fans for my graphics card?

Hi, I'm planning on building a new pc with the budget of 1400 pounds inc. monitor, but I'm wondering if I need to buy extra fans other than the ones that come with the case and the graphics card?

I'll be buying a EVGA GeForce GTX780Ti Classified and the case
http://www.amazon.co.uk/NZXT-Phantom-Midi-Tower-Chassis/dp/B006I2H04I
I will be running at i5 4670k and will be using a Asus Maximus Hero VII with 8Gb of RAM and 750W power supply.

So, do i need to get more fans? Or are the default fans provided by the case and graphics card enough? I don't really plan on over clocking it any time soon so I won't need to buy more fans right?