"QuickMailer is a snappy way to send email from the menubar" - lifehacker.com
"Why can’t sending an email be as painlessly fire-and-forget as sending an IM? Enter QuickMailer." - cultofmac.com
"QuickMailer is a real lifesaver." - 9to5mac.com

Send off an email with just two keyboard shortcuts:
To compose email: ctrl+⌥+⌘+m
To send an email (same as Mail.App): ⇧+⌘+d

QuickMailer can send emails using your primary Mail.App account, no configuration is needed.
Or, if you don't use Mail.app, it can be configured with custom smtp settings*.

The menubar item glows red when you have unread mails.

You have the possibility of making the app remember individual fields (to, subject, message, attachments), so that they are right there ready for your next email. Quick, mail away!

*SMTP supported on lion and above. (NTLM authentication not supported)