I've been a Bloglines user for a while now, and before that FeedDemon. FeedDemon is excellent, but I think I prefer the convenience of an online feed reader. Bloglines is great, but I get the impression that nobody is actually working on improving it or supporting it. I tried a switch to Newsgator Online, but apparently they have a brand new version in which the kinks aren't out yet. I'll definitely give them another try because they seem to have promise.
I was happy to see this article on TechCrunch: The State of Online FeedReaders.