I don't use FireWire for anything, but it is a superior technology to USB. While USB 2.0 is rated for theoretical speeds higher than FireWire, in reality FireWire performs much better. It's like ATA vs. SCSI. With USB, the CPU of the host machine must manage the connection while FireWire has dedicated hardware for that. FireWire also allows for memory mapped devices which means that the CPU doesn't need to be bothered for copies.

I don't care that FireWire isn't in the new MacBooks, but it is a much better interface than USB. I don't have FireWire devices and don't do anything that would benefit that greatly from FireWire (like video devices or external hard drives). However, I can understand why people who had invested in FireWire devices or people who would benefit from the better interface would be annoyed. The problem for those people is that, just like SCSI, very few people need the advantages of FireWire.