Questions about fw400 and eyetv

Hi everyone. This is my first post and I need some help.

I just purchased an eyetv500 and want to get an external HD. The one I have been looking at is the Lacie 500GB FW. I like it because it has 2FW ports and 1USB. So here are my questions.

Is FW going to have that much faster of a sustained transfer rate if I am mostly transferring HD tv shows? I would also use it for Time Machine.

Since it has two ports, would I be able to connect the HD to my iMac, then connect the Eyetv to HD with the second FW port. I have a 24" iMac Alu 2.4 and it only has one FW400 port.

The last question is wether or not any of this is worth it and if I should just get the USB HD for 40bucks less.

Any help would be great. I havent even gotten the eyetv(still in shipping) but want to order the HD asap.

Thanks in advance - and sorry for the long first post.

pedro