Seeing as everyone is posting old news, I thought I'd post this. Four videos showing off various Half-Life 2 related things for XSI. Also, it shows off the glare on the eyes, which is amazing.
Also there are two new interesting things about Half-Life 2:
Judith Mossman: A female character that's apparently very important.
Lamarr: Something female that gets out of a cage (you have to watch carefully to find the references to her). I think it's a headcrab, personally.