In need of external hard drive

Hi so this year i will need an external hard drive for my school work, my school asks for at least 50-100GB but i would like something along the lines of 700gb+ as i currently have a old external hard drive of 500GB but it is a terrible one (has a power supply, needs a 120volt plug to use it) and that hard drive is more or less full of movies and TV series and would like to download more movies to put on that so 700gb+ would allow me to have plenty space for my school work and enough to add more movies. any help is appreciated. my at-home desktop has 3.0 usb plugs so if the hard drive was in usb 3.0 it would be awesome  

Note: i live in canada so my favourite websites are Newegg.ca and Ncix.ca

my budget: around 100$

those are the hard drives i saw sofar:

http://ncix.ca/products/?sku=70920&vpn=WDBBEP0010BBK%2D...

http://ncix.ca/products/?sku=74984&vpn=STAA1000104&manu...

http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...