I have seen some comparisons between the seagate drive (though the 1TB version which should be a bit faster) against the velociraptor, and the velociraptor is a bit faster in sequential read (about 10%) and of course it has a lower latency which is great however the test is not very conclusive as of the "absolute" best, in the other hand the performance gap between the VR and seagate will stack up as you add more drives to the RAID. However I would preffer to go for 1TB RAID rather than VRs due to the extra noise and the not so great performance gap.
As for your SSD question that depends on ow much you willing to spend and what is the minimum storage capacity you will need. I recommend you to take a look at the laptops forum since SSD is a very common topic in there.
Overall if money is not an issue then intel/samsungs are your best choices (intel's 80GB ~= $400 if i am not mistaken)
in the otherside you can get 128GB of a G.Skill drive for ~= $200 (its the one I got) which though it will not stand a chance against the itels and samsung's its just good enough to buy you some time until you can get the really good ones for cheap.
Here is a review of my drive:
https://forums.macrumors.com/threads/661948/
and here is a link to the 64GB version which should be enough to run the system + your most common programs.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231220
do not be fooled by the "not so great" sequential read from xbench, remember these drives have a .1ms latency only! also while you are not doing nothing the system will be quiet (unless fans)
anyway good luck.