It has an excellent Primark just across the road from Debenhams.
I taught Genealogy in Piccadilly Manchester for a number of years and the buildings around there are amazing. There is also a brilliant Police Museum that is worth a visit as it contains some amazing reconstructive displays.
the Manchester Jewish Museum also is worth looking at as the Jewish community in Manchester was behind a great deal of the commercial and urban development of the city.
The Manchester Record Office has a huge collection of material and one of the sources used often is the records of the railway companies in the area, who were giants of the industry.
Oh one thing that is interesting about Manchester Cathedral, there was a short period of time when the incumbent there, would carry out mass weddings, several couples at a time could be married and they could be from anywhere in the Country and as long as they swore they were free to marry they could be. If you research the registers (I think in was around the 1860s) you find dozens if not hundreds married in one day. This is why a random marriage in many Families can seem to have taken place in Manchester Cathedral when in fact the couple both appeared to live up to 80 miles away, and very often Family Historians have ignored the marriage thinking it was the wrong one. However, for many reasons, whether they be religious, family or legal, couples would walk for days to reach the Cathedral for the ceremony.