An article in New York magazine suggests a few British actors for parts in the Half Blood Prince movie:

• Jim Broadbent as Horace Slughorn
• Bill Nighy as Rufus Scrimgeour
• Daniel Day-Lewis as Marvolo Gaunt
• Kristin Scott Thomas as Narcissa Malfoy
• Ian McShane as Fenrir Grayback
• Michael Sheen as the Prime Minister

Remember that these are just thoughts as to who would be good for the parts, we don’t even know which characters will be cut from the movie.  I think Bill Nighy would be really good for someone in the movie, he was great in Pirates as Davy Jones. And the other people sound pretty good too.

Thanks HPANA!