Thanx!! I too think of Rutger Hauer as the perfect choice for Jason Blood, he seems to have that mature look without being too old just as the character... and the feeling that there is something far more powerful and ancient about his personality than just his age (or the demon inside him). BTW, I think the perfect choice for Merlin (in the Etrigan mythos) is that guy (can't remember his name right now) that played Bishop in the Alien movies.
On a side note, did you notice that two of the most popular mystic characters in the DC Universe who were opposite forces had almost identical alter-egos? Jason Blood / Etrigan the Demon and the former Spectre, Jim Corrigan. They both looked in their 40's (in the comic at least), were redheaded, and had a white stripe of hair above their foreheads... funny...