Depends what type of video - if AVCHD then possibly it might struggle a little in that area - considering the rest of the spec and the likely price it doesn't make sense to compromise here - I guess Sony put a 4200rpm drive in to keep the power consumption down, figuring the user would use the HDD for long term storage and the SSDs when speed is required (but then the OS + programs will probably be on those). However you can get 7200rpm laptop drives that apparently use the same amount of power as 5400 drives ie. Seagate ST9320421ASG etc.
You don't say if it's 32-bit or 64-bit Vista, but remember that 32-bit will only give you 3.25GB of usable memory.
p.s. bet it's not cheap, especially with the SSD drives and Blu-Ray burning (not to mention the Sony Vaio badge)