Get a PC without an OS and then install Ubuntu. You'll have most of the software you'll need without the DRM of Vista, or the extra fees associated with Office.

You could even get a image now, and use either vmplayer (I think) or run it straight from cd (on boot, with no install) to get a feel for it.

Yes I'm an MS hater (because time and again, the company has proven they are willing to screw the customer in the name of profit. Hell they come right out and lie to everyone so they don't have to play nice with other people).

If your thinking mac. Just wait for it. Spring isn't that far away, and it lets your money gain interest in the bank.