Xian is known for the capitals city in china for the noddles and dumplings which are two types of the local foods you can't miss.
Just to try the local noddles and noddles randomly along the street, you can find a lots of those restaurants.
Jia Shan soup dumplings (贾三汤包）and liaoliu soup dumplings( 小刘汤包 are nice dumplings restaurants in this city.
You can find a museum book at the warriors museum, very nice picture and infromative which is best souvenirs over there.
Hope this can help
Edited: 8:48 am, June 17, 2013