A little over a year ago I compared the jobs available for PHP, Django and Rails (http://news.ycombinator.com/item?id=805931). I did the same again 3 months ago (http://news.ycombinator.com/item?id=1459119). A quick glance now shows the same trend and ratios (eg, simply hired has 20,125 PHP jobs, a 25% increase in 3 months; 5,334 Rails jobs, a 39% increase in 3 months; and 1,153 Django jobs, a 25% increase in 3 months).
TL;DR: PHP, Django and Rails jobs are all on the rise, there are vastly more PHP jobs than either Rails or Django jobs and there are many more Rails jobs than Django jobs, and this applies to startups, too.