... Naomi Watts!
This lovely leading lady (and personal favourite of mine) turns 41 today! She is so talented, but I believe that she is underrated compared to a lot of the actresses around her age. Taking a look back at her performances in King Kong, 21 Grams, The Painted Veil, and Eastern Promises, I would consider all of them among the best of their respective years.
On a side note, Naomi Watts was recently in Toronto to promote her new film Mother and Child, which I foolishly chose not to attend. It has been getting some good buzz since the festival, and hopefully will find a distributor soon.