That hybrid hard drive from Seagate is pretty good. It's a 750GB hard drive with an 8GB SLC SSD cache. However, I don't think that it'll compare to a true SSD, especially if you use a lot of data.
I don't know what you mean by rampage, but if you meant your Raptor, then yes, you can use it as a backup drive. It shouldn't slow down the SSD unless you mean RAID 1 which would probably slow down the SSD. However, if you just make regular backups, then it should be fine.
If you're looking to spend so much on an SSD, then I recommend that you consider this:
http://pcpartpicker.com/part/ocz-internal-hard-drive-vtx425sat3512gm
Vertex 4 is one of the fastest SSDs available and considering that I found it for about $400 for the 512GB model, it's very well priced too.