Pumpkin,
Blowing your roots is an acceptable mid-point (IMO) just wrapping the hair and blowing it all out. I prefer to blow my roots only when I go to a DS because my hair gets just as straight, retains some of the movement and body that the rollerset gives it, and leaves the older more fragile ENDS of my hair untouched.
Pumpkin...no disrespect to Marvin...but you should do what YOU want and what makes YOU most comfortable when it comes to your hair. You know your hair better than anyone else. Blowouts can cause damage but they don't have to and if they aren't causing damage to your hair then it shouldn't be a problem.
Everyone's hair will respond differently to this method (blowing the hair after a rollerset) so even some of the experiences you get on this thread won't be accurate for you. So trust your instincts, go with what YOU know about your hair, do what YOU want, and watch your hair carefully. Ultimately, no blowout will have your hair falling out over night. It's safe to play around a little with this and see what happens.
Again - to me, blowing my roots gives me the best of both worlds when it comes to MY hair.
HTH /images/graemlins/smile.gif