I recently bought a FF400 to be used with Logic on my imac, but it doesn't work.  Some weeks later I have been told that i need a different firewire cable to run with my model mac.  Would have been handy to know this a month ago when i bought the item.

What are the best cables/brands to look for?

Is there any other problems I could encounter, like latency or reduced signal quality?

I have no need for an external hard drive and certainly don't want to drag one along for live performances so the cable is the only option for me.

Any advice will be gladly received.