I may be weird but I like the email accounts (and calendars) separated. At least give us the option and not go one way or the other. I've seen some posts from iPhone users that there are too many menu options in Adroid, I don't think there is enough, I want more choices not less.
Depending on what you want to do with it, you could have all of your gmail accounts filter into one 'main' gmail account via the web interface. That's how I'm set up right now. I have my 'main' gmail account checking my other gmail accounts, and my droid is set up to link to my 'main' account.