The big buzz in the uber nerd world is just that. Apple didn't have enough room for FW400 or a full sized display port in the new design.
Looking at the MacBook's new NVIDIA chipset and case, it does appear that there were size limitations. I know previously Apple has acknowledged that FireWire controllers take up space. That's why it was eliminated from the iPod line.
However, that's no excuse. I would be surprised if FireWire 800 doesn't make its way back into the next revision of the MacBook. Possibly when FireWire 3200 is introduced to the Pro line.
However, with mini-DisplayPort I completely disagree that it was done to save space. Apple has a long history of creating proprietary "mini" versions of display standards such as mini-DVI and mini-VGA.
They have plenty of room on the iMac line, yet still ship a mini-DVI connector instead of the full-blown port.
I would assume Apple thinks the full-blown ports are aesthetically unappealing and would also like to sell $30 adapters.
For those that don't know Firewire's history ...
Apple was one of the last manufacturers to adopt USB 2.0. It took them three years from the introduction of USB 2.0 to even ship their first product with the standard, the PowerMac G5.
Ironically, they were the first to ship a computer with USB 1.x ports.
When USB 1.1 hardware became hard to acquire, Apple even went as far as to clock down USB 2.0 hardware to 1.1 speeds in the last generation PowerMac G4.
They spent years building Firewire up — getting hard drive, consumer and professional audio and video manufacturers to adopt it — only to drop it when it actually becomes a standard.
Dell offers Firewire on practically all their products as a either a standard feature or cheap upgrade. HP and Sony generally just include it.