How do you handle your email....

I have an snet.net email address. Usually Ive always used Yahoo to log in and look at my mail and such.
However, Id like to use a mail client but the only drawback I see is keeping the Yahoo site mail in sync with my mail client on my home computer. For instance, if i check my email with Windows Live Mail application on my home computer, the email will no longer by on the Yahoo site. Unless I chose the option to keep it on the server, however, I noticed a problem with that method. Windows Live Mail will download duplicates.
The reason Id like to use both is for when I am at work or away. Id like to keep them both in sync and have not found a fool proof way of doing so. Id like to have access to all my old emails as well if I am away but would like to use the application on my home computer.

How do you all do it? Not sure if I explained it well enough but is there a method of being able to accomplish what Id like to?

Im not exactly sure if Yahoo does or not. I am looking and some say yes, others no. But I cant find anything on the settings so I can try it out.

Yahoo's Zimbra desktop might be your best bet - Yahoo! Zimbra Desktop

Thanks for the help. I tried to use those servers you mentioned using Windows Live Mail, but the authentication failed for some reason.
I am going to try the Zimbra app that z3r mentioned and see if I have any better luck.

okay, Zimbra is working right now. I chose to option to synchronize the folders, and it is processing it now.

Now this set it up automatically. I take it I cant view the server settings it used? Or is this only accessing the server and not actually downloading the emails so the emails really arent stored locally at all?