So these are the two books I ended up buying today. Now I don't know which one to start reading. Both are immensly long, and both come very highly recomended. So which one should I read first?

I can't read both at the same time, b/c that would be too much. Plus I am reading A History of God, but that's nonfiction (or is it?), so I can handle mixing the two.

I haven't read Shogun, but I give a major thumbs up for Pillars.

Flip a coin. Both books are excellent. Shogun is quicker to get "hooked" on, IMO. However, once you get "hooked" in POTE, you won't put it down. Despite my interest in Japanese history and samurai warfare, I think POTE is the better book.