question for Adobe "premier Pro " and /or "After effects" users.

i biult a PC for a cousin a year ago and , he wants me to upgrade it to give him an increase in performance for using video editing software etc .he has a 4 core 2.9ghz processor and 8gb of ram , he also wanted me to look into upgrading the graphics card (currently onboard)

he has 2 sata 2 hdds raided(o) and was until recently happy with the performance .

i am more than happy to double the RAM and fit a graphics card ,that in itself is no problem .but I cannot help but think that maybe a fair sized fast SSD  would give him a better performance boost as a scratch disk than the memory ,though he would do both if I reccomended it .

personally i dont do video editing and as such have never had the need for this form of upgrade .

anyone here have some suggestions ,and a graphics card recco at the same time ,cost is not too big a problem ,but I dont want to spend the earth as its only an upgrade .

thanks .