Summary: I actually just left a review for an external hard drive I bought in January '11 from Western Digital noting the good experience I've had with the brand. I had forgotten that this hard drive was also a Western Digital. I purchased this in September 2009 after the original hard drive in my Mac unexpectedly died and as of today, it's still going strong.
Summary: For less than $50 320GB is a lot space and made my purchase a real bargain. I considered a 5400 RPM HDD keeping in mind heat and consumption. So far so good. It's a very silent HDD and it seems pretty fast. Western Digital is a brand with reputation. Nonetheless, I couldn't find any information about product registration and warranty.
Summary: bought this to upgrade the 80gb drive on my dell latitude d620. plugs right up. loaded windows7 on it (4gb ram on my 620) and immediately i saw drastic improvements. its not only less noiser but response time was greater. would recommend if you have an OEM 80-160gb drive for your dell latitude d620 for sure. no regrets.