Which is the Better Value?
Ultimately, value comes down with what is best available at the time of purchase, and what your computing needs are. If you are building, or shopping for a new computer and want the best available components available, then DDR3 will suit your needs. Most new computers that are equipped with a double-core, triple-core, or quadruple-core processor will most likely come with DDR3 memory. Although it is possible that some models will still come equipped with DDR2 memory.
For desktop computers, a 1GB stick of DDR3 can cost up to $20 or more; a 2GB stick of DDR3 can cost from $25 and up (some sticks cost over $100). Keep in mind that some of the DDR3 RAM below $50 include brand names such as Kingston. So these are no cheap, no-name brands being mentioned here. As for DDR2, the prices are more or less the same. The difference is so minimal, it is not even worth mentioning. Though it should be stated that the DDR3 price drop does have something to do with that. Naturally, desktop RAM will always be less expensive than laptop RAM, and consumers must always keep that in mind.
The better value, due to the recent price drop of DDR3, will definitely have to be DDR3. Do keep in mind that if your current computer supports DDR2 memory, you can only upgrade with DDR2 memory. Same goes with DDR3 and the original DDR memory.