well, depends... i mean, i am not telling you to go and get 1 GB of DDR SDRAM, but 128 MB of it is fine considering that it is not that expensive. but for the average user who only surfs the net... naww. that's right, the average user does not play games on the pc.
for those who do, DDR would be good, depending on the game. some games just require A WHOLE LOT OF RAM.
DDR will help with my video work, which is just amateurish...