The average size of a video game has increased substantially over the years, so it's just as well that storage upgrades aren't anywhere near as expensive as they used to be. But if you've only got one ...

Conventional wisdom says if you're building a new box then you should use an SSD for your system drive. Compared to installing the OS and apps on a spinner, the claim is of night and day difference.

If you won't have any space issues on your 500GB drive (and it doesn't sound like you will since you're only using half of it right now), then it makes more sense to leave that OS X installation on ...