I don't recommend striping since if one of the drive goes, your entire raid volume is gone, unless you plan on getting a raid + mirror, if you are using 2TB stripe, you'll need a 2TB drive to mirror, not sure if they even make those..
IF you do go the Striping route, COPY ALL YOUR DATA FIRST, then create the stripe, during the creation process, it wipes the data from any drives that you are using for the striping, after you have created the stripe, you can copy you data back.
I suggest just attaching an additional hard disk and start moving stuff into that HD, so if one goes, you only lose some of your stuff and not all of it.
Another option maybe? external HD that are USB 2.0 spec are pretty quick, the small 2.5" factor external HD cases does not require external power supply, it gets all its power directly from the USB ports, but 2.5" HD capacity highest I seen is 300GB. The big normal HD cases does come in greater size but requires a power brick.