should i do a raid setup

[2-tall]

i am looking at building my first pc and was wondering if i should go with the raid set-up. will it make that big of a difference and is it possible to just add the other hd sometime down the road if i decide to do it?

[Force Flow]

There's not much of a real benifit unless you're running RAID5. Mirroring is just a waste of a drive that you could use for good backups instead; striping will increase you chances of losing your data (since 2 drives go to act as one); JBOD, the same reasons as for striping.

You can always add another HDD to your system as long as the PSU will support another device. If you try to incorperate it into the array, it will have to be destroyed (again, all data is lost) and rebuilt.