As a PhD student who starts his last year, I will soon start to look for post-docs. In this process, I will update my Curriculum Vitae. But as a title of this CV should I put "PhD in XXXXXX" or "PhD Student in XXXXXX" ?
(+1) to Chris Gregg's answer. In addition to that two points:
If you claimed to have a PhD (at the time of application) and you don't officially have the degree one can claim you are making a "false statement" and disbar you from the selection process.
[Assuming you want to finish your PhD first and then take up a job] You want your possible employer to consider you for a position after you finish your PhD. Saying you are a "PhD" already means you are ready for immediately employment. Furthermore you might want to have you employer know you might need a couple of days off for your viva, etc. Given that this might take place in the first couple of months of your employment and probably you are not allowed "vacation-time" yet, it is good to let them now early on.