The Velociraptor is a good medium between the expensive but fast SSD and the cheap but slow 7200RPM HDD. It may be more expensive than a regular 7200RPM drive, but it is still cheaper than an SSD with the same capacity. I got my 240GB SSD on sale, and even that was $410 CAD.
Oh, forgot to mention. Never use an SSD simply for storage - that is a huge waste. With an SSD you want to minimize writes to prolong the SSD's life, since they are limited to 10 000 write cycles or so. That is, unless you want to store data on there and never delete it and want fast access to it, then by all means do it, but I still think the performance is better used for programs.