Well, here comes the good news, I think. Google. Your phone is a google phone, that means you have access to Google Maps. Using layers you should be able to do many of the things you did with Mobil Me.
Your calendar will sync to Google Calendar. Your mail will sync to Gmail. It's all one big happy Google family and there is not charge for any of it.
Google talk replaces iChat. You can access all of this from your phone or your computer. I'm a Mac person myself and I love it.
For just about everything else that I see that Mobil Me does, there is a way to duplicate it with your Droid. The only thing you really can't do is sync your phone to a Mac. That's not going to happen. But with Google you can access everything anyway. You can even link your imail, ical to Gmail and Google.