Sheffield is home to the English Institute of Sport and 2 Universities which have excellent sports facilities and coaching. Someone has already mentioned Ice Sheffield, which is part of Sheffield International Venues and has strong links to EIS and the Universities.
Sheffield Teaching Hospitals are renowned (Northern General, Royal Hallamshire, Weston Park (Cancer), Jessops Women's and the Children's Hospitals) - again, excellent facilities due in part to the masses of research being undertaken by the Universities.
As far as the city itself is concerned, it has loads of history and is the 4th largest city in England. It is the greenest in Europe (having acres of ancient woodland and public parks) and has comparably low crime rates. The theatres regularly feature as being some of the best in the UK (largest theatre complex outside London) and there is a great music scene and plenty of live venues.
Sheffield is on the edge of the Peak District National Park/Derbyshire so within a few minutes you can be out in the open countryside.
The housing and secondary schools (Tapton, Silverdale, High Storrs, King Ecgberts, King Edward VII, Notre Dame (Catholic) and Meadowhead) in the south west of the city are generally deemed to be the best. Look at the Ofsted website for detailed reports and the school websites for more general information as they each have 'specialisms' and that may be relevant in due course when your child is ready to look at A levels. Once you've settled on a school, you can then look at houses in the catchment area of that school. Just to make it complicated, some housing areas are split between school catchments but you can find out which postcode area matches each school by looking at the Sheffield Council website.
The best place to look for houses is rightmove.co.uk. Dore, Bradway, Totley (S17), Beauchief, (S8) Millhouses (S7), Whirlow, Parkhead, Ringinglow, Ecclesall (S11), Crosspool/Sandygate, Fulwood, Ranmoor (S10) are broadly relevant to the schools mentioned above. Be aware though that parts of Ecclesall have a high proportion of student accommodation.
I love, love, love Sheffield and I'm not alone. The retention and return of University students is enormous (I think I'm right in saying that it's one of the highest, if not the highest in the country) because it's such a great place to live - it was voted the happiest place to live in the UK in 2013 and not much has changed!
Good luck!