The first time I saw him was playing Angel in the BBC's Tess of the D'Urbervilles. He played the character really well and it helps that he is so easy on the eye.
I have just ordered Pillars of the Earth, partly because I saw he was in it.
(its on sale now on amazon)
You'll enjoy that! It's where I first noticed him - I saw Tess, but didn't really register him. Then when he was in Pillars I thought he had something about him. It was Songbird where I really sat up and took notice. Seriously, Pillars of the Earth is really good and the Rufus Sewell is yummy in it too