I build my own computers, and my computer can/will be able to handle any of those :P So I guess which ever is better, either taking the card out or firewire'ing it.
FW800 will likely be around the same speed as eSATA. But not as fast as USB 3.
For our Sandy Bridge desktops, there will not be any internal readers wired to any headers on the mobo. The machines will have USB 3 and USB 3 ports on the front of the case wired to mobo headers. On the back of the case will be USB 2, eSATA, and USB 3 ports. I will be using external USB 3 reader with the desktop connector to the front ports.
But out laptop does not have USB3. So for it I will continue to use the expresscard reader. It is twice as fast ast USB 2.
Once USB 3 gets out there a bit more, we will likely see FW and eSATA begin to die out. I can't believe anyone will implement FW3200.