Yep, for the most part PCs use a 32/33 PCI bus. The biggest problem can be that one device can make the entire bus slow down. But, there are some new PCI controller chips that have 2 busses off one chip. That should help to get a few faster slots in future motherboards. Unfortunatly Intel chose to make an AGP slot instead of pushing better PCI implementations to consumers. The reason I day that is due to the fact that video cards are the only common device in a consumer PC that could push the needs for a faster bus.

1394 reb b though will need a faster bus or risk flooding the PCI bus. Keep in mind Apple is probably going to call this interface "Gigawire". So be ready for another confusing round of 1394 naming schemes.