It sounds like you want to be looking in the south-west of the city (depending on where work would be) which is well-known for its schools, good housing, relative safety and a mix of good parks etc. Be aware that all postcodes have better and worse parts, but think of Sheffield as a clock face and you won't go too far wrong with the section between 6 o'clock and 9 o'clock.
S7: Nether Edge, Millhouses
S8: Meersbrook, Beauchief/Abbey Lane, Norton
S10: Crookes, Crosspool, Nether Green, Endcliffe, Fulwood, Ranmoor
S11: Banner Cross, Ecclesall, Whirlow, Greystones, Sharrow Vale
S17: Dore, Totley, Bradway