Look at the refurbished Macs. Yes, that means they’re used; but they come with the same warranty as the new versions, and whatever was originally wrong with them has already been fixed.
I bought my refurbed MacBook Pro about a month ago, and was pleasantly surprised to learn that the unit they sent me had twice as much memory as advertised. I was expecting only the standard 4 Gb, but they upgraded me to 8, for free.
iWork is ok, but I don’t think it compares to Office. It’s what a $50 price differential between the two (Home Edition)? Just spend the extra money and get the better product, you’ll thank yourself in the long run. Also, don’t forget that Office 2011 is coming out next month; If you buy a copy of Office before then make sure to sign up with M$ for the upgrade program; they’ll give you the latest version without having to pay any more.
That might be true of apps like Pages (compared to Word) and Numbers (compared to Excel); it is definitely not true of a presentation app like Keynote (compared to PowerPoint).
Most graphic designers and presentation specialists would much rather work in Keynote than in PowerPoint; everything works better and looks better . . . and you can even save your Keynote project as a PowerPoint file.