Here's something I noticed about AA filters. A few months ago, I took some pics of an old adobe church with a Sigma DP2 Merrill. One of my favorite shots has a decaying window covering about 1/8th of the frame. There was a very fine mesh screen across the whole window. It recorded every single strand of wire in that screen, very crisply and distinctly, against the darkened interior of the room behind. One of the sharpest, "bitiest" images I've ever made.
Then I printed it at A3+ size on my Canon 9500 MKII. If you get your nose right up to the print, you can see interference patterns that I attribute to the very high frequency pattern of the screen image with the equally high frequency of the nozzles in the print head. Looks really strange, as if some strands in the screen are missing. It's definitely an aliasing problem, and it would not have occurred with an image of lower spatial resolution, or an AA filter. I could probably get rid of it easily if I reprinted, just by changing the print magnification a small amount either way.