Yeah, I love Amnesiac and I think you picked pretty good selections to introduce somebody. Especially How to disappear completely. That's Thom Yorke's favourite Radiohead song. I'd add the recommendation of these, which are a good accesable starting point:
Fake Plastic Tree's -
http://www.youtube.com/watch?v=3-F5L1S7LKU
and
Just (Best music video ever, and it shows that they can ROCK) -
http://www.youtube.com/watch?v=R5X7HKxpiQA
Have you heard Like Spinning Plates live, Fluffie? I love it so much more. Also, if you like The Clock of Yorke's solo album... listen to this live rendition. It gives me goosebumps!
http://www.youtube.com/watch?v=huXb6lLLy10