I grew up in Houston so I'll offer my thoughts...
Pasadena and South Houston (they are seperate cities, but inextricably intertwined) are pretty bad. Not the worst part of Houston by a long shot, but still unpleasant.
Very poor, polluted, urban wasteland with a fairly high crime rate.
However, there are several nicer suburbs within spitting distance, and rural terrain within a reasonable commute.
Personally, I think Houston is pretty miserable. Hot, humid, filthy.
But you can live alright in the area if you find a good place.