You should look into http://www.stampready.net - along with Campaign Monitor's email builder (https://www.campaignmonitor.com/features/create-custom-email...), it's one of the best drag-and-drop tools for creating really good, responsive emails. The problem with any of these tools is that they still spit out sometimes convoluted code, but that can't really be avoided since they need to cover their asses in literally dozens of different popular email clients.

If you're looking to code, you should check out Litmus Builder (http://litmus.com/email-builder), a code editor specifically built for email design. Has a bunch of templates available, instant previews in a bunch of different clients, email-specific CSS inlining, etc. Full disclosure: I work at Litmus, but even if I didn't, I'd still use Builder for the previews alone.