Bjord3D has reviewed a Seagate's 500GB Barracuda 7200.9 SATA II hard drive:

From what I've seen on the Web, the 500GB Barracuda 7200.9 isn't the fastest 500GB drive around, but it's also not the slowest performer either. Obviously, I didn't have any other company's 500GB drive on hand to see for sure, so you might want to do more research on the drives if you are interested in having the absolute highest performance and highest capacity. Where the Seagate 7200.9 drive does win out over other 500GB drives for sure though is the price and the warranty.

While 500GB drives are not as cheap per gigabyte as smaller capacity drives, the Barracuda 7200.9 500GB drive is one of the least expensive on the market at the time of this writing. Expect to pay right around $300 for this drive and even more for competing 500GB HDDs. That comes out to $0.60/GB or more, which can be about twice as much per gigabyte when compared to 250GB SATA drives.

One reason I find myself recommending Seagate hard drives frequently is because of the warranty. The Barracudas come with a 5-year warranty while all the other competing 500GB drives are covered for only three years (this warranty length advantage applies to other capacities as well and not just 500GB). When a drive dies, it can be quite frustrating and costly, so having the ability to get it replaced for an extra two years is great. A couple other things to keep in mind about the Seagate Barracudas is that they tend to run a bit cooler than the competition, and they also typically draw a bit less power.

When you look at the big picture, the 500GB Barracuda 7200.9 SATA II hard drive has a lot to offer, including solid performance, reliability, great warranty and a good price when compared to the competition. If you're in the market for big storage, do yourself a favor, and put this drive on your list of considerations.

Pros:
+ 500GB!!! (only takes two for 1TB)
+ Good performance
+ Less expensive than competition
+ 5 year warranty!
+ 16MB cache

Cons:
- More expensive per gigabyte than smaller capacity 7,200 RPM drives