If you want nightlife, the city centre is the place to go. The large selection of restaurants, pubs, and clubs will satisfy any drinker's needs. The culture is also great, with friendly people willing to give you directions or help. In Sunderland, there are quite a lot of historical sights nearby, including Penshew Monument and Hylton Castle.
And how can you forget the shopping--with large shopping malls springing up everywhere, you can't help but shop.
Quick Tips:
If you are coming during the summer, I suggest a trip down to the local tourist information centre; this can give you a wide selection of leaflets and may supply you with a book of coupons that will allow you to get in laces half-price and stuff.
Best Way To Get Around:
In my opinion, leave the cars at home! Although there is a large selection of carparks to park in, the best way is to either walk or get the bus. The train and metro service is also excellent.