In a few months, Microsoft will release 64 bit Windows for X86-64. If you buy an Athlon 64 system now, it will come with regular 32 bit Windows XP. If you wait a few months, it will come with Windows 64 bit installed. Even 32 bit software will run faster using 64 bit Windows rather than using 32 bit Windows. With 64 bit Windows, you can run 64 bit software side by side with 32 bit software. You didn't mention your price range and what you plan to use the pc for. There are some other advantages to waiting as well for higher end systems(in addition to lower prices). I don't know if 64 bit Windows will be out around March, or if the release will be closer to midyear. Microsoft said to expect it in the first half of '05.
Is there anything major on the horizon that would keep me from buying a new desktop now, or should I wait until a few months into the new year? Any response would be appreciated.