The short answer: No.
If you were scheduling your next PC purchase around the release of Vista, then this isn't the first time you've had to adjust your plans. You won't find a Vista-equipped PC under the tree this year, but you should be able to bring one home shortly after the new year. Microsoft's latest Vista delay is more likely to cause chuckles than anguished cries from consumers who've been following Vista's rocky road toward release. (Those shedding tears are the PC vendors whose holiday selling season suddenly looks a lot less merry.) If you're fed up with the delays, there's no reason to wait; the hardware exists today to run Vista.
If your PC is on its last legs and you (or a friend) are comfortable installing an operating system, you need not wait for Vista's eventual release before buying a new PC. Plus, nothing says this latest delay will be the last. To ensure that the PC you buy today will run Vista when it's released, familiarize yourself with the suspected requirements. Microsoft has yet to finalize the requirements for Vista, but this page
on its site offers some guidance. From what we've heard, to run Vista, your PC should feature a 64-bit processor on a current chipset, a bare minimum of 512MB of memory (though 1GB is a safer bet), and a DirectX 9-class graphics card (or an open x16 PCI Express slot for a future graphics upgrade).