I have a new web project that I am starting that will offer paid membership\subscriptions. Before I endeavor to write it from scratch, I thought I should check out if a CMS package would offer a decent starting point. If anyone could throw in their "2 cents" given the following criteria, it would help me a lot:

• ~ possibly 5000 - 10,000+ User Accounts
  (Options for Paid Full Membership AND Free Scaled-Down Community Membership)
  (Possible Parent\Child Account Ability)
  
  
• Ability to +\- (and incorporate) user-related DB fields as well as field\table relationships
  (I don't want to "monkey" with the existing AKA Core stuff as much as added custom.)
  
  
• Site Advertising Management
  (Banner Ads, etc.)
  
  
• Possibly an incorporated Web Chat Service for Customer Support

I know of: Drupal, Joomla, Mambo, PHPNuke, PostNuke, TYPO3, and XOOPS.
However, I have no clue which one, if any, would be my best bet; having all or most of the functionality above.

Thanks, in advance, for your time, patience and insight...

If you plan to do heavy use on users and access control, go for drupal but if the current structure of joomla is ok with you... then joomla, I personally use joomla since most the structures of my websites fit nicely to Joomla's model.

I prefer Drupal, but if you need do heavy use from it, seems there are some benchmarks that assure e107 is faster than anyone.