I'm planning to get a new Mac Mini for my girlfriend, to upgrade her from her current G3 iMac. I'm trying to decide between the $500 and the $600 model. She doesn't need wireless, so is it worth the extra $100 for a slightly faster CPU and an extra 40gb of hard drive? Or would it be better to go with the cheaper model (considering I'm also going to have to buy a monitor somewhere) and buy an external HD if the machine ever needs more space? I'm not sure how much an external HD costs right now. Oh and any advice on a cheap monitor would be appreciated too (what/where to get). I'm thinking maybe a 17" CRT, just because I don't feel like dropping the cash on a flatpanel. Thanks!