I have now a ~500GB and a ~250GB Harddrive, and 3/4 TBs are enough for me.
I used the second one fr, like four years and
it still isn't near to full OMG ONLY ABOUT 4.7GB FREE!!!
But oh well, I still have the first hard drive which is only halfway full, and I still have to throw away all the stuff that is still from by brother's PC (My old HDD with 200GB
exploded flushed itself down the toilet was eaten by my cat died 2 weeks ago, and I was too lazy to format my brother's HDD and reinstall XP.)
Good thing that I kept all the important files on my 2nd HDD!
And remember:
Several small HDDs are sometimes better than one freaking huge HDD.