That's my advice, for what it's worth!
At the very least, divide into two. The main C: partition would be used as normal, operating system, applications etc, but you would use the second partition for all your personal data.
That way, if you ever have a major crash that needs a re-format and install, all your personal data will be unaffected.
My own 120 GBt drive is actually partitioned into four, but that's just my personal choice.