From which type of store can a computer get its data most quickly?

Technically, the computer gets its data from the RAM faster than any data storage technology available. HOWEVER if you are talking about storage data, than it would have to be the ridiculously expensive FDD or Flash Disk Drive, with data transfers of over 100MB's a second for the more outrageously priced models. These are hampered by the fact that the largest FDD you can get is 128GB at this point in time.