I am getting the exact same board and was wondering the same thing. So I just read and read this board to find out what to get.
I'll be going with the following:
Silenx 120mm fan (IXP-74-14B)
That Thermalright has gotten some great reviews and we all know a Silenx fans are ultra quiet with great airflow.
Do a search on them if you like, you'll be happy.
Hope that helps.