Use SSD for boot/app or DB loading... for this purpose alone, if you say a hybrid drive is enough, you are crazy..
A modern SATAIII SSD tops 500MB/s... and you definitely feels it comparing to any mechanical drive out there... hybrid or not.
If you happen to be on Mac, do what I do... I have SSD for boot, a 500GB 2.5" for temp. big files and a Promise Pegasus R6 for storage.