There are literally hundreds of options for eating out in Manchester, and in recent years, as the city has redeveloped, the standard overall has improved dramatically.
The city was once an important port, and people arrived from all over the world making for a real cosmopolitan culture on offer, and a thriving China town, where almost every Oriental cuisine is on offer, and one of the better restaurants in the area is Teppanyaki - a Japanese restaurant which offers good value and great surroundings to enjoy while you eat. If you like things spicy, then Pacific is a good Thai restaurant just around the corner.
21 Piccadilly is another modern choice that also has a nightclub on the premises, and is popular at weekends.
If you don't do meat, then the best veggie restaurant in the city is On The 8th Day, where you can enjoy a wide-ranging menu with plenty of cruelty free choices.