Collapse question

When I was in the beginning stages of writing "Collapse", I made it a point to try picture each of the characters in my mind. I figured that the easiest way to do that would be to cast them for the big or small screen. I would like to share my thoughts and would love to hear yours as well. I haven't cast them all, a few of the major characters remain as generic figures in my head. Here's what I've got.

Howard Beck - Malcolm McDowell
Maxwell Harris - Mark Ruffalo
Richard Dupree - ?? Big action star obviously
President Powers - Denzel Washington
Stacy Reid - Katherine Heigl
Elizabeth Reed - Amanda Righetti
Spider - Seth Green
Head - Me. The character is a little jab at myself.
Tank - "Stone Cold" Steve Austin
Roberto Jimenez - Edward James Olmos
Hal - Patrick Stewart

There are other characters introduced after the sneak peek, don't want to spoil anything just yet.

Thoughts?