iMac buying - 512mb or 1gb of ram?

Lt Major Burns

"Dicky" Charlteston-Burns
i'm looking to buy an iMac for a friend. she will only ever use iPhoto, itunes, messenger, safari and word and possibly photoshop simultaneously under tiger. will 1gb be too much/512 be slightly too little? is it worth the upgrade. she's adamant she wants it, but doesn't really know why