That hub needs to be connected to both a USB and Firewire port to work. You just plug it into a USB port and the Firewire ports do nothing.
In your second example the firewire drive wouldn't show up. Firewire and USB are completely different protocols.
I'd happily buy a MBP if I had the cash to spare, but I'd rather something smaller. I carry my MB with me pretty much everywhere, on my bike, so size and weight makes a difference to me. I also hate glossy screens, they suck for using on stage if you're DJing or doing something where you need to see what's on the screen. I don't care how good Web 2.0 pages look on them.
For the price of a MBP I could get an iMac for the studio and a discontinued Macbook for portability. I'd keep this MB but it's kind of destroyed, two years of work/gigs/location recording takes it's toll on a plastic case...
Oh, and it also shits me that they're selling the old bottom of the line MB, with a Superdrive, for less than the new ones so they've still got a cheap model. So it's $300 less for a more powerful (2.1GHz vs 2.0) machine that still has Firewire?