I have never set up an account on my Nexus One in the 1.5 years I have had it. For the most part, it works just fine.
But I cannot and have never been able to locally setup calendar appointments. I would love for you to tell me I am wrong, but I have no working calendar on this phone.
K9 mail works awesome with my own email server. I can set alarms. But I really could use a working calendar (everything that is add-on seems to use Google calendars as a back-end, and/or requires obtaining it via Google's app market, which obviously I can never partake in).
Otherwise, life is good.