I'm sorry to hear about your website being deleted.
I have been using Joomla! for the clan's site, and I find it spectacularly awesome. Joomla! is being developed by a part of the original team that was working on Mambo. So it's pretty much the same thing. The difference is that Joomla has a bigger tool repository. (
http://www.siteground.com/joomla_mambo.htm)
If you want to try it out check this link out:
http://demo.joomla.org/ .
Or if you want more control over Joomla there are free hosting sites that come with it preinstalled. (FreeHostia).
For what I see, everything you want can be worked out.
Splash page: Create an HTML page (index.html) with desired animation and linked to the site's index.php (which is the one used by Joomla).
Blog: There are extensions that for that, some are even based on WordPress.
Forum: Same as above; some are even based on phpBB3. There are also native forums for Joomla.
Download area: If you are the only one uploading these files it's just a matter of placing the links in the Downloads section.
Little sites for pictures and text: What can be used here is maybe a photo album that supports text? If that's not enough check
http://extensions.joomla.org out. It has all the supported Joomla extensions.
Cron jobs are programmed tasks. Under Linux cron and crontab can be used (
http://www.scrounge.org/linux/cron.html), under windows I guess that Scheduled Tasks can be used.
I'm also driving through Joomla's learning curve. If you need any help I'm more than available. At the moment I am playing around with Joomla and SQL. Shortly will start with Ruby on Rails (pretty neat too!).
PS. Nobody uses splash screens anymore
