Any 2.5" SATA laptop drive will work. Now for the fastest speed, you can go SSD, but you won't get a lot of space but fast speed. I would suggest if you go for a normal hard drive, get a 7200 RPM drive as they are faster than a 5400 RPM drive and will decrease you load and saving time. Don't know what to suggest as you don't give a budget or how much space you want, but as I said, any laptop sized, 2.5" SATA 7200RPM hard drive will do.