App Name: MailDroid [Android Email App]
Developer: Flipdog Solutions
App Market: Download Page
MailDroid is a Webdav/POP3/IMAP Idle Push mail client application.
It is also a secure mail app supporting PGP, PGP/MIME and sMIME. The app also have a custom spam plugin for people that want a client side spam checker. MailDroid supports multiple email accounts for your email management (as many as you like with no limitation on mail accounts). There is also a pro version that is ad free that adds a few additional features.