I personally prefer Firewire for direct pc to pc hookup because it seems easier to configure plus, it's used for transferring video which means it's a high-speed port.

If both laptop and desktop pc have firewire, I'd go with that connection. Just make sure you have the right cable since there's 3 kinds:

4-pin to 4-pin
4-pin to 6-pin
6-pin to 6-pin