it really depends on what you use it for.  if you word process or surf the net, probably not.  if you game, maybe ... it really just depends.

RAM makes a VERY big difference in your system's speed, no matter what you do with it. That is, unless you already have like 512+ mb.

Well thanks for the info....

Let's put it this way.  It probably won't hurt you, and it's probably the most cost effective upgrade you can buy.  That's not saying you will necessarily benefit from the performance increase -- but again, rams cheap -- so telling people to buy a lot of it is, in general, good advice