I have the earliest Mac Pro and it has dual Gigabit Ethernet ports so it ought to work. Gigabit Ethernet is still faster than USB 2 and FireWire 400.
Since it's so easy to take drives out of a Mac Pro, the other option is to spend about $40-80 on a dock with USB 3 and stick 'em in there to do the transfer.
USB 3 will be nice and fast on a new MacBook Pro, even if not as fast as Thunderbolt.
I like to have a dock anyway for backups, since backing up to bare drives is cheaper than buying fully encased externals.