Software suggestions please..

I'm new to WPMUDev and WPMU software in general and, given the vast selection of software offered here, I'd like to solicit suggested software configurations for the following.

I'm in the process of setting up three niche sites within my own WPMU network. Each will have a unique look and feel but they may share content, engage in cross-promotions, etc.

The plan is for each to offer a mix of public and subscription content and each will have a forum, perhaps with free and paid forum areas if practical.

So my question is, given the vast array of WPMUdev options, what would you suggest in the way of themes, forums, plugins, etc. that I can start with as my base configuration?