Mass Effect, I grew to love everyone, Ashley, Wrex, Garrus, Tali, Kaidan, Liara, Joker.... everyone.
Seriously, I actually felt hurt when I had to sacrifice Kaidan but I had also grown too attatched to Ashley to lose her, and I went crazy making sure Wrex lived as well.
Same with Mass Effect 2, I went insane making sure my whole team lived.
Also, I don't know if this counts but in Halo 2 and 3 I worked like mad to keep all my elites alive in combat.