Is there a difference between SATA and SATA2? I'm looking to upgrade the hard drive on my macbook, I've found a Seagate Barracuda 7200.10 320GB Serial ATA II Internal Hard Drive(16mb cache) and a Western Digital Caviar SE16 250GB Serial ATA II Internal Hard Drive(16mb cache) and Samsung 250g SATA II(8mb cache) all for under $100. Are these the correct types of internal drives I should be looking at for my macbook? Any recommendations?