It's difficult to give you a list of night spots, especially since most of us don't go out clubbing in Tokyo any more. I've found that more so than the place, any given experience has a lot to do with the people you meet there and interact with.
BTW the bad rap everybody gives Roppongi is really about the main strip with bars, and annoying touts out front. A street or two away from there and it's like just about anywhere else -- quiet, restaurants, residential areas. Of course there's a much much higher proportion of expats. I've been there many times just to hang out with friends, eat dinner & whatnot. The location typically picked for the convenience of all who were joining or for the particular restaurant/bar.
As far hot new attractions go, you can't get any hotter than the world's first
Snoopy Museum which just opened. It might even help you with the ladies. When they ask you what you're doing in Roppongi, you'll say,
Oh I came looking for the Snoopy Museum. Then you'll show them the little plush Snoopy you bought and their hearts will melt.