If you deal mostly with write-intensive situations, then the Western Digital RE3 Enterprise 500GB is probably going to be the best machine for you. It comes with a dual processor for faster performance and sports IntelliSeek, which allows for lower power consumption. It runs cooler, which gives it less chance of burning up.

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What's really nice about this model is that it's quiet, which can be quite a plus in already noisy situations. The major downside to the Western Digital RE3 Enterprise 500GB is that it's a little pricey at above $100 for its drive size.
Another set of Western Digital drives are the Caviar Black 1 TB (approximately $200 retail) and the Caviar Green. The Caviar Green (approximately $200 retail) uses 40 percent less energy than a standard drive and is supposed to be extremely quiet. It too has up to 1TB of storage space, allowing for that needed extra space for anyone dealing with many or over-sized files.
The 1TB Caviar Black is also a prize because it is so fast; it comes with a dual processor to improve speed. These models also come with a five-year warranty, which means by the time that you are ready for an upgrade, your warranty will be just running out.
Another Caviar model is the 80 GB 7200 RPM Caviar EIDE Hard Drive. This inexpensive model (approximately $50 retail) is great for those that just need some additional space, but don't need to worry about extremely large or data-intensive files. It is a good fit for the average desktop consumer. It can load about 100 MB per second, which doesn't make it the faster model, but a fairly reliable one. This long-lasting model also cuts down on noise and heat.
If you have the cash, the Western Digital VelociRaptor (approximately $300 retail) is probably the fastest machine on the market with its 10,000 rpm speed. The problem with this machine is the low-end 300GB memory, but it has some of the highest ratings for reliability. So, in fast-paced industries, including security and financial industries, this is probably the machine best suited to your needs. It too comes with the five-year, industry-leading warranty.