I also have 500GB, and used more than 60% of it with W7, lots of movies and games, developer resources etc.
And when I purchased, dealer was saying that 250GB is more than sufficient, you'll never need that much(i.e. 500GB)
I've 250 GB HDD and I've used about 80%. its contains many of software and Games[as i am crazy about New Software and Games] and about 30 GB for videos tutorial and Help books and also lots of Movies[Only Hollywood] and rest spaces for others document
any one knows , how to recover files cheaply from crashed HDDs. I have one 40GB, 80 GB and 250 GB HDDs all are crashed and I didn't have any back ups. I want to recover the 40GB HDD because my college days photos and my year project was lost in it