On my Motorola Droid, I was able to set up Hotmail as an Exchange Active Sync account. I followed the settings in http://windowsteamblog.com/windows_live/b/windowslive/archive/2010/08/30/hotmail-now-supports-push-email-calendar-and-contacts-with-exchange-activesync.aspx and everything worked fine. However, on my wife's HTC droid incredible I can't get it to work. It seems like I cannot leave the Domain field blank on the HTC Sense acitvesync Account setup.
I tried various tricks like using "." or "\" for the domain field, but no luck.
Other users have apparently faced the same issue - http://community.htc.com/na/htc-forums/android/f/91/t/5031.aspx, http://androidforums.com/desire-support-troubleshooting/180574-exchange-activesync-hotmail-failed-create-account.html, http://androidforums.com/incredible-support-troubleshooting/162643-anyone-have-hotmail-exchange-activesync-working.html,