* I believe Windows has seen more architectures than Mac OS Classic and OS X combined.*

I have never been a Windows user, but I used to keep an eye on it when NT was still the separate business version (pre-Vista) and my NT 4.0 (or was it 3.51?) CD-ROM had x86, MIPS, Alpha and maybe PowerPC support. When things weren’t as clear platform-wise, NT was really a multi-platform system. Since then also x86_64, IA64, ARM64.