The Product: Western Digital Scorpio Black-A 2.5" SATA laptop drive that runs at 7200RPM in sizes up to 320GB. It's the best combination of speed and size of any notebook drive on the market today. And it's got a really cool name.
The Price: $250 as tested (320GB, 16MB cache and freefall sensor)
What we see here is that the Scorpio is much faster for sequential reading and writing (dealing with big files and stuff organized physically close on your hard drive) but actually slightly slower for some random reading and writing (dealing with smaller chunks of data floating more freely on your hard drive).
But isn't the WD model supposed to be faster? Sure. But it's also over twice the size of my old Seagate. Such a test supports the classic ideology that an OS should be stored on a smaller drive quarantined from your other data to keep running quickly. Laptops rarely have that luxury.
That said, I haven't noticed anything running slower since the upgrade, but have noticed a few things running faster (that I don't think can be contributed to hard drive placebo effects). My 500+ site RSS reader loads quicker. And within Final Cut Pro, scrubbing the timeline is completely effortless.
Potential downsides: The drive makes an almost inaudible whir and seems to vibrate ever so slightly more than the old Seagate. This could have to do with the drive or the fact that my hands are less precise than the army of deft children's fingers piecing together Macbook Pros. As for battery life, WD claims it sucks no more power than their 5400 drives, but I can't test the theory with my aging lithium ions.
Final Verdict: Overall, for $250 (or less), it seems like a no-brainer upgrade to store more media...given how much this fancy machine cost me in the first place.