Multisite + Buddypress - need help

I'm building an online community for people suffering from agoraphobia ( I want users to be able to create their own blogs, and have it be a community site, but have all the new sites have the same look/feel and menu as all the other sites... a multisite that feels like you never are actually leaving the site. I don't want users to feel like they're creating a wordpress blog. I've installed easyblog, and a bunch of the plugins, but am looking for a way to more easily customize the feel of each blog. I'm struggling with finding the right theme, and kind of lost on the plugins I should be using, and how to use them. Thank you!