I think there's nothing at all wrong with stem cell research.The lab I used to work in used adult mesenchymal stem cells, which come from the fat taken out of liposuction patients. There's absolutely no harm in that; it's a biological waste product that would otherwise be thrown away and never benefit anyone. Even embryonic stem cells are not taken from anything in a way that would deprive someone of life - when fertility clinics combine egg and sperm from the mother and father clientele, they create more than they need and use them up until one of them develops properly into a child. Those that don't can't really be used in anyone else (the parents wouldn't allow it) and if the parents don't want anymore children, these extra cells - like the extra fat from the liposuction patients - would just be thrown away.
Stem cell research can benefit almost anyone suffering from any kind of disease. It might eventually help in regenerative medicine, and in repairing failing organs of old and ill people. Research in this area also helps us better understand some diseases, especially neurodegenerative ones. As for gene manipulation, it's kind of a different topic, but I think as long as it's for a solid reason (like preventing genes that predispose you to cancers or inactivating a gene that would cause a disease) and not for something like hair and eye color, it's perfectly legitimate.