Most of my textures come from free sites as well. Though I do use some of my own, as well as making my own lightmaps by hand. Many of my textures, I reuse, just as Cyan does with theres in other ages I work on. Little coloring here, different UV map there, and the texture looks like its a new texture, when really its the same one. This is found throughout uru, and I see no reason why we shouldn't do the same. I even go so far as naming them like Cyan did, with the first four letters of the mipmaps name being the original age i used it in. That's just an OCD thing, and I don't even have OCD.

So, my two cents, if you want to use CG textures. Use them. If you want to hunt down textures at free sites, do so. (As long as they're not copyrighted I see no reason not to. And if you want to take a camera out and make your own do so. There's only so many textures you use before you run out of space on a hard drive, and realistically speaking, if Cyan reuses textures both CG and real, i see no reason why we shouldn't as well.
Now, I'm off to work on figuring out clusters.