While all the reasons for linux not 'feeling' as fast as windows booting are very valid and interesting for me, I am not going to explain all that to my girlfriend. She will just say OK and boot into windows if all that she wants to do is check her hotmail. And, yes, when she powers the machine off, she doesn't care how long it takes- shes not waiting for it. Why can't linux shift some of the things it does during boot to doing them during shutdown?
If it did, it wouldn't be Linux. I'm sure if you really wanted to hack the startup scripts and take things like syslogd, and a hand full of other daemons or background them you could save a few seconds. However, Linux's roots is Unix and Unix runs on computers that stay up 24/7. If you don't shutdown, just log off and turn your monitor off, it will be as fast, if not faster than Windows.
Rob