I really don't understand modern art. No matter what I hear otherwise, if it looks like a blue square on a white background, it is a blue square on a white background. And yes, anyone could do that. If there's some reason deep meaning behind it, I'd rather hear or read about it and possibly understand the thought process, but I can't be impressed with the art.
As in many other areas, I tend to be drawn to unusual content, The fact that my favorite artist is Hieronymous Bosch only proves this. If you can look at The Garden of Earthly Delights for the first time and not be at least a bit shocked, I'd be surprised.
My first exposure to Escher came while reading Gödel, Escher, Bach a few years back. Since then, I've seen an exhibit showing prints of most of his works, and a few other books, and will eventually have a print of something (not sure what) hanging on a wall here.
I don't want to get into any details (it's better to be silent...), but I've almways been most fascinated with the early Flemish style of painting, around the time of Van Eyck and some others whose names I've forgotten. The fact that so much detail exists on (often) such a small scale is incredible.