I used the Source family briefly. It's quite nice, although there was something I didn't quite like about it. I replaced it with the Nimbus L family, which is very similar but seems easier to read to my eyes. (on X11, anyway. doesn't look quite as good on OS X for whatever reason).
I added some notes to the blog post about customizing horizontal and vertical spacing of the text. Advanced editors and terminals usually have a setting where you can fiddle this for your own comfort.
The horizontal spacing of Consolas and Source Code Pro are almost identical. The vertical spacing of SCP is much greater, but you're more likely to be able to adjust that in your editor anyway.
DejaVu Sans Mono can be better in some environments http://dejavu-fonts.org/wiki/
I also discovered I like the new Ubuntu Mono http://font.ubuntu.com/
except it has too much vertical spacing, but I hope to find a way to easily edit that someday