Christina Aguilera just starred in the movie "Burlesque," and she just sung the "Star Spangled Banner" at SuperBowl 2011 Pre-show. Both performances show that she has a strong voice! (Although, she did stumble on the lyrics of the national anthem.) By the way, I thought the anthem was traditionally lip synced to avoid last minute jitters? Regardless, Christina Aguilera gave a soulful performance of the anthem and a professional delivery despite a minor imperfection in the lyrics!
Now as far as Christina's hair, I love her blonde look.
In order to achieve this look, Lightener (i.e. hair bleach) is needed if you have Black, Brown, or Reddish hair. If you have "dirty blonde" or lighter hair already, then skip the Lightener process and choose a high lift blonde permanent color. Process according to manufacturer's directions. If you still have some brassiness then tone it down with an ash/violet base semi/demi permanent color. Always shampoo and condition between color applications. Paul Mitchell has a Super Strengthener that can be used after shampooing the lightener from the hair in order to strengthen it for the semi-permanent toning color that can process on wet hair.
A Healthy hair note: In order to keep hair healthy, it is not recommended to go lighter than three to four levels from your natural level. For example: Going from black to blonde is not healthy for maintaining long lengths. Going from a brown/black into a reddish brown is reasonable to obtain and maintain length. Also, going from a light brown to blonde is reasonable to obtain and maintain healthy hair.