it's not really the OS comparison..
it's IIS vs apache
apache wins hands down for speed..
also for windows, it's important to ensure that the table names don't get all lower cased (windows default for mysql install)..
otherwise, moving FROM doze to nix will be a pain, if it ever is needed
another thing is that you have to do non-secure things, if you want to use imagemagick on windoze...
as for a personal preference: i choose linux for ubbthreads, but windows won't kill you
