Got my PE in earlier today and have been working on tweaking it. Set up the Froyo mail to sync my calendar and contacts but didn't really like its look for email. The other default email(old version of K9 mail) didn't handle notifications well. However, after using Titanium Backup to uninstall the default mail client, I was then able install the newest version of K9 off
http://code.google.com/p/k9mail/downloads/list It works really well. I turned off notifications from the Froyo mail (left it set up so it'd will keep my contacts/calendar) synced. And now K9 is setup as my primary email. Might mess around with the google apps install later, but for now, this seems much better than the default options.