(I'm just going to cut and paste my answer (slightly changed) that I wrote just now in another thread.....)
Even if you don't use FW, I'd rather it be included, as it has been included in every Mac for 8 years or so. There are no good excuses for not including it. Apple just wanted some way to differentiate the MB from the MBP. If they were really so concerned with product differentiation, they shouldn't have designed them to be so similar.
FW has huge advantages over USB that not even USB 3 can solve.
1. The constant, sustained throughput of FW. USB only transfers data in bursts.
2. USB uses your CPU, and therefore, slows down your computer. If you're moving a lot of data, or you're using a device plugged into your USB, be prepared for your computer to slow down. Firewire doesn't require the CPU, so you and your computer can continue working at full speed.
That said, only the cheapest, s**ttiest camcorders don't support FW. Just because people buy the lowest end camcorder doesn't mean that $1300 and $1600 laptops shouldn't support FW. Even midrange products that are on the lower end of the scale have FW.
Besides, if USB was so effing hot right now, then why not replace the FW port with a 3rd USB port? Even $350 netbooks have 3 USB ports, and they actually dominate the laptop sales figures at the moment.