Oh and the poll assumes everybody uses just one machine, so I can't vote
At home:
1 Windows 2003 Server
3 Windows desktops
2 Linux servers (one is used as a TV/Media server)
2 Linux desktops (both Suse)
1 Dual boot
and I carry a bootable Linux based memory stick to use at various places as needed.
At various places I work for it's a mix of Win/Lin, Linux mostly used on servers.