Domain names and quality content go hand in hand – it’s not a case of one over the other, rather it’s a case of getting both together to make a kick-ass blog.
However, depending on which stage you are at in your blog’s life-cycle, each factor will have a different role to play and understanding that role can help you make your blog more successful.
In the short run, right after launch perhaps, the name of the blog is perhaps one of the most important selling and branding elements available to the blogger. You can do more and go further with a good name and average content as opposed to an average name and good content (I’m talking about short-term results, the first few days or weeks after a blog’s launch). Since it’s a new blog, people will give you some leeway when it comes to product quality. However, if you are average in your brand (name), people won’t remember you as easily as they would remember the other blog with the cool name.
In the long run, however, product quality always trumps the ‘cool’ name. So while having a good name will help you in the beginning, in the long run you can have a successful blog by taking an average name (not a bad name though) and build a brand around it simply by consistently providing your readers with quality content.
So how important is the blog name and blog branding for you?
The answer to your question is more complex than the long-run / short-run analysis. It really depends on 1) how you monetize and 2) how much you depend on repeat traffic and 3) how much you depend on SERP traffic.
I have strong evidence that a solid keyphrase domain name, with reinforced keyphrase loading, can land and keep you in the top 3 spots for fairly strong two and three word searches that are worth thousands of dollars per month simply for referral commissions. If you monetize through SERPS (almost always new customers) then a strong keyphrase domain is essential.
But, if you plan on building a business around repeat customers, you are right…quality of product wins the day.