Agree about there being a difference in performance in favor of a SSD. Yes, RAID config with solid states can improve performance depending on the configuration. If you have the ports available and the cash, RAID5+1 gives you the redundancy, a hot spare and killer performance. Sadly, there aren't a lot of motherboards out there with 6 SATA ports of 1 variety (My ASUS 990FX has 6 SATAIII - waiting for the day I can afford 6 on my drives). Easiest way to get serious performance with a RAID config would be RAID 0 - you won't get any redundancy so if a disk fails you're fracked but you'll get killer read/write speeds because it's using 2 SSDs as a team to find/write data.
If price is a concern, it's important to determine exactly how much...