Email fowarding and Mail rules!
I already talked about using rules in Mail, but I just started using rules in a new way and I think it is really great. I have more and more email addresses depending on who I am talking to, but keeping track of all the emails is becoming a problem. Of course, it is not really a problem with Mail because it is easy to have multiple emails checked automatically. When I am using a mobile device (Blackberry, etc), or using webmail, I prefer to have all important emails at one place. It is why I simply redirected many email addresses to my main email. I still want to be able to quickly spot where the email came from. It is why I am using the Mail rules to apply color labels: