I'm in the same boat as you, Jay. I was trying to decide between a Powerbook and an iMac before the iMac got upgraded - I was leaning toward the Powerbook (I didn't think the iMac would get upgraded), but I didn't know what it's update would be like. Now, I'm leaning toward the iMac, but I'm not sure - I have a laptop now, and I might miss the mobility. I'm waiting until next wednesday to see how significant the Powerbook upgrade is. If it's minor, I'll get the iMac for sure. If it's average, I'll have to think some more, and if it's major (like the iMac's upgrade was), I'll probably go PB.
We'll just have to wait and see...