A nice compilation of emailing campaigns with interesting design. Good point : emails are organized under different categories for you to easily find inspiration with a particular topic, ex. account activation, welcome email, newsletter and so on.
And if you want even more inspiration, check out the following site, in French this time, but also with nice resources (over 1,000 newsletters indexed) :
The Mailing Book :
une galerie d’emailings destinée
aux créatifs et rédacteurs.