A survey conducted by Eloqua, Software Advice and CMO.com called the 2012 B2B Demand Generation Benchmark Survey shows that B2B marketers will put their main focus on SEO, email marketing and social media in 2013.
The channel popularity has turned out like this:
As you can see, email marketing is on top (yaay!) while direct mail, retargeting and print/radio/TV are at the bottom.
Lead quality was also part of the survey: the results show email on top as well:
You can find more results of the survey here.