Which e-mail client does everyone use? Google? Yahoo? Outlook?

We currently use Verizon web mail and hate it. I want to set up something with more control and that we can have accounts directly for our domain. ie instead of for instance.

"my-email@verizon.net" it would be "my-email@mydomain.com"

I have heard both good and bad about several. Just curious what most folks prefer.