There's been a lot of talk about Bochs as a possible alternative since Microsoft acquired Virtual PC last month, but one idea published in BusinessWeek got my attention: integration of x86 emulation into OS X. Waow. Mac OS X would become the most versatile OS out there.
Perhaps even as early as the upcoming Panther release (you know, the one after Jaguar OS X 10.2), Apple users could pop a Windows CD or DVD into the drive, and OS X would seamlessly launch Bochs and run the Windows code. In fact, I bet Apple could get this process to run smoothly enough that loading PC software would differ only slightly from launching Mac programs.
If you want to give Bochs a try, download it from SourceForge project page, or check out OpenOSX WinTel 1.0. Interestingly, multiple G4 CPUs can be utilized and are emulated as a single powerful Pentium processor or as dual Pentium Processors. Virtual PC files are compatible, and can copied over from the Finder.