for paying, no idea, but for simplicity I love the picasa software on the pc and then album syncing with ease. As well as the basic manipulation tools.
Flickr just seems to be facebook for snap-happies
I find that a slightly odd comment, I find flickr to be heavily used by some very high-end photogs, where as picasa with its super-simple image manipulation kit included seems to be aimed at the technologically less competent, a place for non-photogs to upload pictures and do simple cuts and changes that a more serious user would do in a proper package before uploading.
Also the flickr uploader couldn't really get much simpler to use.