Sorry that I didn't post my reviews earlier... So here it goes...
Live Custom Domain except that you can have unlimited email accounts and users can automatically register (if the registration is open, which is not needed by me), there is nothing, absolutely nothing provided.
Google Apps (which I am using for my domain right now) allows not unlimited but as much as you specify during registration (I gave 1000 accounts). It provides a customizable login page which can have a customized domain, thats is you can CNAME your domain to
point the login page. You can have your own logo in place of Gmails logo. Secondly it provides mailing lists. Also there is POP3 service. That is all the gmail services with your own domain name.
EDIT: Google Apps also provide catch-all-emails feature and same inbox for multiple domains can be used.
Now you decide! Live must do something to get in lead.