Annoying, isn't it, that MS haven't included an Outlook Express version with 7. I use Windows Live Mail, from which I have disabled the messaging part and only have the email part. Very similar to OE, but not as user friendly.
And MS try to tell us that 7 design was customer driven - I don't think so!
Gone with outlook in the end, not my first Thunderbird was too complicated trying to set up my remote pop3 email accounts and I just don't have the time to persevere with it.