Many nice neighborhoods in Garland: Firewheel area, Oakridge, Camelot, just to name a few. If you work downtown Broadway and I30 might be a choice for you, but the north end of Garland near the Richardson border is also very nice.
North Garland areas including the 75040 and 75044 are newer developent areas near Fire Wheel Mall and along George Bush tollway. I have lived in Garland for 25 years and familiar with the area some areas here are hit and miss just like any other area. Joe is also right about around the Ray Hubbard area 75043 is nice also.