My favourite hair colour of all is ash blonde. However, it's one of the most difficult tones to maintain as without right care it can quickly turn brassy or gold.
The key is to use blue/violet shampoo but remember not to overdo it as your lovely, ash reflects will turn into grey and matte. I usually use the shampoo every other wash and keep it for a few minutes on my hair but only properly wash the scalp because the lather will take of the the longer bits.
Lovely ashy hair colours and styles below.
That was mine a few months ago ;)