How to quickly send new mail without opening mail application?
Check out QuickMailer. It's similar to LaunchBar but I feel that it's easier to use. Here's a screenshot:



If you're a keyboard-junkie like me, it has shortcuts to compose mail and send mail (Compose: Ctrl + ⌥ + ⌘ + m, Send: ⇧ + ⌘ + d) to speed up the mailing process too!

It isn't free, but it's pretty cheap at 99 cents. I don't own it so I haven't tried it out, but I've heard great things about it.

Hope this helps!