I have several external drives just because I'm a bit of a back-up freak. You can get a 1TB (1000 Gigs) drive from Future Shop for about $130. It would be a lower quality drive than the one mykalberta mentioned, but in my experience all drives die and I've seen little difference between the high and low quality drives.
This is still my dream:
The Drobo is a casing that can hold up to 4 drives. Plug it into your computer and it shows as one massive drive. If (when) one of your drives fail, the data is simply shuffled to a safe spot so you never lose anything. Fairly pricey and not something I'd buy unless I had immensely important data, but a man can dream.