Ian Holm is awesome, and his agent is the classiest dude on the planet. I tried to get Ian Holm to do an intro for one of my Let's Play videos and got a lengthy Email back from his agent thanking me for my interest and saying how flattered Ian Holm was that I'd be interested in contacting him, but that he was busy with other projects.
I mean it was probably all bullshit just to get me to go away, but he could have told me to screw off (like Gary Busey's agent did) or just ignored me completely (like many other actors did). Getting essentially a thank-you letter from his agent was a pretty cool change of pace.