512 is probably just fine. That you can never have enough ram is a bit of a dubious statement, sounds like something from the mouths of marketing types whose job it is to separate you and your money. If your gut tells you "go for more" then maybe buy up and get a 1gig stick. More than 1gig for the average home user is overkill. Past 512mb, memory *speed* is as much or more important as memory *amount* The purpose of ram is to have enough of it to run the programs you regularly use. Having more ram than the apps you use requires is pointless- it would be better (performance-wise) for you to look for a computer that supports the fastest memory speeds rather than just buying tons of ram.
