By the way... The Macrumours forum (which I have significant difficulty in spelling but google is forgiving) seems to have been started because they like to speculate (sometimes) about what products are going to be uncovered in the Mac convention held each January. There is a particular forum for that, however, and you aren't supposed to do that in other sections (though people do sometimes). So... You get handy information about whether you are better to leave off purchasing model x or model y if an upgrade is likely to follow the mac convention. (My book was the only one that people thought I'd be okay with since it had a major upgrade in November and I purchased in December).

There is also a more 'official' Mac forum associated with the online official purchase site along with some tutorials on using macs and using Leopard etc etc etc. That one seems pretty good, too. You are supposed to rate the 'best answer' and so people seem highly motivated to up their rankings on the site by posting a relevant and informative answer. But... The official site seems (to me at least) to be less sympathetic about user modifications to hardware etc. And of course to ban speculation on products.

The 'official' site isn't endorsed by mac (in the sense that you can't sue them if you get bad advice). Seems that some of the people who post there are authorized mac genius people, though, but of course they aren't posting AS authorized mac genius people if something goes wrong.

Might be worth checking out there too... (I think you need an i-mac account in order to post, though). But there could be stuff in the archives.