I am looking to buy an external hard drive for my lap top. I am not sure what the most important things to look for are, average seek time, data buffer, maximum data transfer rate, RPMs, storage capacity.. Out of all those could you list them perhaps in order of importance. And in each category what numbers should I be looking for? I really dont want to get screwed over. Just a little extra information I will be using this to store movies and documents as well.
And no one except Google has good data on who's most reliable (changes from model to model and from year to year) and Google's not releasing that data. So I would look at SPCR's test data on heat and power draw to make my own guesses on reliability. Remember, there isn't much airspace inside an external enclosure for cooling.
Speed? I could be wrong, but you're going through a usb2.0 connection, and that may be slower than the hdd. But the whole point of that external enclosure is back up and storage. It does not contain your OS, or your programs, or your virtual memory. So speed isn't primary.