I'd go with the WD Scorpio, as it is much faster than either Seagate option.
Oh really? I was of the opinion from Tomshardware review, that the 7200.3 and the WD Scorpio were neck and neck in terms of speed, but the 7200.3 won for better power management. When you say much faster, how much faster is that?
The 7200.4 is the single fastest notebook hard drive on the market today.
Of course, by "on the market," I mean that you can preorder it - it isn't shipping until the end of February IIRC. Still, it will flatten the Scorpio. As you said, the 7200.3 and Scorpio were neck and neck, and the 7200.4 is a full generation newer than the .3, with several improvements.