[jzf]

A working demo of something you have built and maintained. Seriously. Build something, anything. Put it out there... and polish it. Make it better. Keep iterating. Use it as a vehicle to show your drive/passion/intellect- all the qualities you want your resume to say.

Oh you are a rails developer? Show me your work. This speaks volumes over "3 years of ruby blah blah blah"

my $.02

[volts]

I second this. Learn a stack and build something with it. You will start seeing jobs that you are qualified for and that will put you ahead of the next guy. Look at the job listings to see what's in demand.