The faster hard drive will give you a decent boost in overall speed, and the extra memory will make it faster having several apps running at once. I actually did a similar upgrade on my computer recently and it is running great. For a hard drive, I recommend the Western Digital Scorpio Black, which I bought and very much like. It is quiet, doesn't vibrate much more than the stock drive, and is fast. It's also available in a 500GB version now, which provides even a bit more speed, due to the higher data density. As for RAM, I just bought whatever was a good price on newegg, which happened to be crucial.