The home page of a social site (in my opinion) is the cover of a book and it's the first impression people see when visiting the site.
Having big banners should be ruled out for a couple reasons, a banner is a image, a template is a image there fore it shouldn't stand out as much as what the content should.

I think it would be nice to have a "take a tour" link, image link, button etc. on the home page.
It gives the user the choice to either see more of what the site is about or just see more simply login/register.
This brings me to another suggestion.
Make the home page clean, less cluttered but display the primary purpose to the site (get to the point of what the site is about)

Having a feed is a realy good idea, you can provide feeds that could be filtered by the end user (Photos uploaded, Videos uploaded, Blogs posted, Users joined etc.)

This is kinda out the window here but i'm gonna mention it anyways as any administrator could set this up easily.
Having a default user created with some sample content, on the home page provide the option to take the site for a test run...nobody wants to spend time filling out fields, confirming, logging in to find out it's not quite up their alley.
This gives our users a feel for what the site is about, how it works, what's going on etc. than they can make the decision to join or leave.

Here's a folder with a couple screenshots that contain the outline and gives a general idea as to my opinion...


Oh yeah, where it says new, should have said news :P

I think I like the "Take a tour" idea better than anything else I've heard so far. It's one thing that is really missing from Dolphin. (Considering the complexity of the system)
Below is the legacy version of the Boonex site, maintained for Dolphin.Pro 7.x support.
The new Dolphin solution is powered by UNA Community Management System.