If you figure it out let me know. I've had my site listed at all of the places you noted, plus many others. I actively comment on others photos and cross-post all of the photos from my photoblog to Flickr. My photoblog is in the signature of most of the forums I visit, and has been listed on several friends websites. All of these efforts have garnered lots of visitors but few comments. I average several hundred visitors a day (not including bots), but I have only slightly better than 1 comment per image posted.
I hope you have better luck than me figuring it out, and if you do please share your findings.