Grab your free copy of Poetsen One. It’s increasingly rare to find font designers putting full character set fonts in their free offerings, so I grabbed this one as soon as I saw it. Rodrigo Fuenzalida has a few other fonts available on his site, so be sure to check them out.
I love a nice, clean, well-rounded sans-serif font! Gilroy is kind of a cross between Gill Sans and Avenir; two fantastically readable fonts that work large or small.
Gilroy is a full family of 20 fonts which you can get for $45. But you can grab the Light and Extra Bold versions for free. Download the Gilroy freebies here.
Rockfire is a great display font that’s perfect for titles and logo work. Designed by Jay Cobs, Rockfire is 100% free for personal and commercial use and includes upper and lowercase letters, numbers, and a limited punctuation set.
Chris over at SpoonGraphics has made this Vintage Light Bulb Sign PSD file available free for personal and commercial use. The only thing missing is an exclamation point, but I was able to easily make one out of the letter I in the PSD.