need main features to build a wordpress.com-like blog farm...

Hi, i'm actually building a blog-farm/park, and i'd like to know what i need to install from your site to have it the best way possible. … you advertise that it's the goal of this site, to have the best features etc… but there is too much.

something like wp.com is what i try to accomplish. subscriptions, level of features, themes, domain registration, etc…

i'd like to know what you have to suggest to make it right… i'm gonna pay the next semester of membership if i can have support on this to make it the best site for my clients…

thanks!