I want to build a site that allows users to sign up (either free or advanced paid subscription) and create their own user accounts. Once in their account they will be able to monitor and track pregnancy related things such as ovulation, doctors appointments, some charting and graphing, medications they are taking, diet and it will also provide some other things in version 1. I'd like to release new versions 1-2 times per year with added functionality so this must be scalable.
I have fairly good technical knowledge. I am an Internet marketing manager and can easily code HTML and CSS and know some various other languages such as php and .Net (not quite as well but good enough to look at code and know what it means and do the copy and paste thing!).
Is there a CMS out there that I can customize enough to get what I want? If so, what do you recommend? I have used Joomla (a few sites), Wordpress (MANY sites) and we use Ektron at my current employer. I'd like to stay on the less expensive end if possible but am willing to invest a little to get the right package.
So, basically a password protected website that allows users to track health related things. Thanks in advance for your help!