If I was writing a CMS to manage my personal site, the only user I'd care about is the only user that's going to be using it, Me. But since ProjectX has a far wider audience then just the developers, care needs to be taken to see to it that the users needs are being met. If ProjectX doesn't need users then what's the point in writing a program for a larger audience. Of course, like I said in my previous post, the needs of the users come after the needs of the developers, or else you'll find yourself in a situation where the users bite the hand that feeds it.
Even if you're only writing a program for your personal use, and you don't care about anything but your own needs, finding another person who has the same needs as you and starts using your code would be a huge benefit. Now you have 2 pairs of eyes on your code and any bugs will surface twice as fast. Even if your user never contributes anything but bug-reports, he may recommend your software to another user who becomes a developer, or forks off and creates a whole new beast out of your code (which is a good thing).
So I guess to sum it all up, my thoughts are: if you're writing a program for an audience greater then the developers you need users. If not, then users are an asset. Either way, users are a good thing :)
And, I do get a kick out of knowing that my code is being used by someone other then myself, it wouldn't be enough to keep me working on a project though.