imho the users who needs 8gb ram are as follows:
1) people who use facebook, seriously ever tried facebook with less than 4gb it's not a pleasant experience.
2) twitter users, most phone out there hardly can run this memory hungry thing, when the new iphone is released with 4gb i might consider using twitter.
3) m$ office, this is probably the most memory hungry thing out there. Each time you time a letter it uses memory (do you see where i am going here?) the more you type the more memory you need, if someone is typing up a 20+ page document i would recommend they have at least 8gb, 16gb if you can afford it. There are machine out there like
this that are purely created for word processing in mind.
4) gamers, don't be fooled into thinking just because a game is written to only ever utilise up to 4gb it will only need 4gb. The gaming companies are lying, you need 8gb or ever 16gb it will ensure you have to optimum experience.