I nominate Damian Lewis. http://www.imdb.com/name/nm0507073/?ref_=fn_al_nm_1He is known from Band of brothers, Homeland and Wolf Hall. He is 6'1". He has a good look for the role and does well as a man with a destiny of loneliness and suppressed tragedy.
I also nominate Joseph Mawle. http://www.imdb.com/name/nm1152798/He is an established actor who is perhaps not as well known. This might work well considering Círdan will live through the entire season, people will expect a famous actor to live on while they might think someone not as famous will be killed off in a war. He is 5'11".
I also nominate Rhys Ifans. http://www.imdb.com/name/nm0406975/?ref_=nv_sr_1
His version of The Shipwright will perhaps have a little bit more of bitterness and his tragedy will really show him as a loner, someone who has chosen a path that no one else can understand. He is 6'2" which is good, Círdan should be tall.
Círdan may be a minor character, but he'll have staying power throughout the series, being there from beginning to end (like Celeborn). He will stay on the edges of the stories, having a different vision and purpose than those around him, but he will be marked as someone with wisdom and keen insight from the beginning. He will be one of the few Sindar who remains Noldor-friendly after news of the kinslaying gets out. He will help foster/raise a young Gil-galad, and maintain the Havens at Sirion (and later on the Isle of Balar).
He generally plays villains, but has a gravitas and screen presence that could be used for wisdom as well. He's older, so while Season 2 Círdan isn't bearded yet, we'll see his age weigh him down much faster than the other elves. The Austrian actor is also great with languages.