After always wanting to own a PowerBook, I am eyeing a 1.33 standard model with only 256 ram. I believe the ram and hard disk are upgradable, but I wanted to find out a few things about the machine: 1) What are the advantages of picking the 1.5 over the 1.33? Is the speed really that much quicker? 2) Can the machine cope with SD video on YouTube, without having to use mobile YouTube? 3) Can the machine take 2.25gb of ram, or only 1.25 (not officially, but in reality!) 4) Would a flash drive work with this machine, without issues? 5) What OS would people recommend? Would leopard run OK, or should I stick with Tiger? Many thanks for reading, in advance!