Good Email-marketing plugins

I’m looking for a plugin that will let me add a newsletter signup form to one of my webpages, the signup form must be fairly easy to customise (if I could specify my own HTML template that would be great).

I’ve looked at a few plugins but none seem to work the way I want. Most recently I’ve looked at ALO EasyMail Newsletter, which looks great except for the fact that the ‘newsletters’ are just indications of blog posts, which isn’t really what I’m after.

Any recommendations?