I consider the MacBook (especially refurbs) to be one of the best deals around right now, it's what I use for a personal computer.
But for MFD capture I would recomend spending the extra money and getting the MacBook Pro if only for the three gigs of RAM you can load it up with. Besides that, it also has FW800 so if you want or need to shoot to a card you can utilize the Extreme FW reader or just hook up externals for backups.