Woody's does have some killer karaoke, from what I have heard.
Serious answer is it is hard to answer without more info. Tons of good restaurants, but it depends on what kind of food you guys want to eat. If you want to be a true tourist maybe ditch the nice food and plan on Pat's or Geno's late night (there are better cheesesteak places in the city though). Steven Star still has a few restaurants in the city and they are considered top in the country. I guess a laid back kind of nice meal might be at the Continental or something. Looking at a list (
http://www.phillymag.com/foobooz/50-best-restaurants/) I haven't heard of 3/4 of those places, but might be a start.
Also depends where you are in the city. I am guessing center city, probably near old city. there are bars literally every single block, so it won't be hard to find something you might be looking for. depends on the scene you want and your location in the city. the night life has always been good (in my opinion) so there are options galore.