When I am working at home (or in my case trying to find work) I use an e-mail client. For years at my office, I used a program called GroupWise. It was a Novell product and only works on their servers. It was a great program. It was like having a client and web mail in one, because it had the flexibility of an e-mail client, but all the e-mail was on an offsite server, in a bunker that had backup generators and internet connections.
Today, at home, I use Outlook to check my Gmail and by ISP mail. On the road or vacation, I use my Blackberry and then go to the appropriate web based e-mail if necessary to respond or look at attachments.
I use to hate Outlook--still not my favorite, but it has some cool features in the 2010 version that makes it more interactive with the other programs in that suite.