I wouldn't worry.
From what I've read, most OEMs and other hardware firms have embraced both technologies. And Firewire is leveraged in that it has been out longer and has more devices already made. Also the next generation of Firewire has some distinct advantages over USB 2.0--much faster, lower power consumption (lower than Firewire 1 from what I've heard!), power able to go throught the cable to devices, etc. And it is backwards compatible! (Just like USB 2.0).
It seems like both Firewire and USB will continue to be on the market with Firewire continuing to be the high-end and USB continuing to be the standard for things like input devices.
You can find tons of firewire devices out there: hard drives, cd drives, cd burners, dvd players/burners, digital cameras, digital camcorders, mp3 player (at least the iPod, any others? I'm not sure). Anyway, there are a lot.
I've got a CD burner and the iPod for Firewire and I couldn't be happier with them. And any advantage USB 2.0 has pulled is a result of the Intel marketing machine. They do a superior job at marketing the inferior
Matthew