The grey area of software licensing IMHO.
You know, if I own 2 Macs onto which I want to install iWork 09 and I shall not use them concurrently, then I won't feel bad in buying one copy and installing it on both Macs.
TBO, I am in the same league. I use my Mac Pro at home most, but my MacBook Pro at work most. I have bought the boxed version of iWork, and have installed it on both. Maybe technically not completely legal, but I don't feel like a pirate.
Must admit, that I might buy the Mac Box set as-well anyway. That way, I feel that I have done my best. Yes, I will be installing 3 copies of iWork and iLife and Leopard on 3 different Macs. And I have 2 licenses of everything....