I've really got a thing for clean typographic blogs with seemingly custom illustrations in them. Above is a great collection of vintage woodcuts and engravings, scanned and released for public use. That is, you can download them and use completely free in both personal and commercial projects. I think that's wonderful, and if your more interested there's a Terms of Service provided:
You may use our pictures in your school projects, to make CD sleeves, posters, banners or any part of a website, in animations, etc - anything where you have added your own artistic effort, be that for educational, personal or commercial use. No credit is required in this case. This is how it's done.