I currently am using an OCZ Vertex 3 120GB with updated firmware. I've been using it for a month, and I've already been seeing it for cheaper than I got it for ($110). Can I still get another Vertex 3 for RAID 0 even after I've been using one of the SSDs for a while? Thanks.
Yes. The normal requirement for RAID0 is that the two drives have the same capacity (With SSD probably best if the two SSDs are the same). "New" or "old/used" is not a factor.
.. You lose trim comand, although I understand Intel is coming out with a new driver that will suport trim when the drive is a member of raid0 conf - Only applies to Intel chipset controller, Marvel and AMD have not announced this support. The Newer SSDs do have a Better Garbage Collecter, BUT it Still Performs better with trim
.. The Biggest benifit of Raid0 is in the increase of Sequencial read and writes. Access time is unchanged and the Improvement in random 4 K is small. High Sequencial performance benifits working with LARGE file structures that are ON the SSD, even with a 240 gig SSD I don't think yo're going to stick a Bunch of 10 gig photos, or very many DVD/Bluray movies.
Both My two desktops and one laptop have daul SSDs ( Before SSDs, I ALWAYS used Raid0 on HDDs). In all three systems I chose to use one SSD as the OS + Program drive and the 2nd SSD as a "work" drive (ie placed most often used files on it).
You can get another for RAID 0, however being as fast as SSD's are - I highly doubt you would notice and real - world difference.
Once you have such fast SSD's - everything else seems slower - your external USB HDD/Flash keys would be limited by their own speed/firmware/controller, as well whether or not it is USB 2/3.
The main benefit of having 2 SSD's in RAID 0 would be encoding media or transferring large amounts of data quickly. However you would need equally fast external storage to accept those fast transfer speeds - since Vertex 3's would do about 1GB/s reads and writes (probably a bit less depending on the controller, as well as overhead).
In my opinion I would spend it elsewhere depending on what you already have.
Maybe save for a new GPU (looking at your specifications)?