Bird Help?

[funnel101]

We've got a very outgoing small bird that likes to walk on our back steps. It's about 3", mostly brown, with a ruddy red patch on the back of its head. I haven't been able to identify it in either of my bird books. Either the potential match is the right size with no red patch, or red patch but way too big. Anyone have any ideas?

[EDIT: It's a house finch.]

[EDIT 2: It's a purple finch.]