I haven't used Geddy yet. But most server side NodeJS frameworks are more complementary to the client side MVC ones like CanJS. I found node-restify a good fit. Express for my taste is way too concerned with rendering views and handling sessions.

Well it provides the REST webservices that a Model needs. So basically all the server concerns nicely separated so that it can be be used by any client side MVC framework.

That's what any classic server side MVC framework does. Just the same as the Zend Framework for PHP, Ruby on Rails or ASP.NET MVC, Spring MVC, Django etc. Generate HTML and spit it out. It's just using JavaScript instead of PHP, Java or Ruby to generate it - so imho mostly still the same mistake but in a different language.

Exactly. That's why I was looking at Restify. Occasionally I am still working on my own little framework on top of that which hopefully will make creating REST services even easier and more HTTP compliant.