I like this one. I like photos that pull you into the center of the photo the way this one does.
You have nice detail and a good texture visable. The only thing that might have helped here would be cropping differently to get that first cross bar out of the image the out of focus bar is very distracting. Also don't be afraid to resize closer to the 640 for the largest side.
There is a nice feel to this picture. I love teh focal qualities, but I don't like that it is nearly square. I really dig teh zig zagging of teh black irrigators? nice shot - I even envy your "wine country."
The out-of-focuse line at the bottom takes a lot away from the photo as it tends to draw my attention to it. Aside from that, it is very nicely composed and gives an almost serene feeling to the viewer.