Seeking a robust, full-featured RSS/Atom Reader

I'm a poweruser. It's no surprise that I am an early adopter who likes to test out the newest and coolest software applications. I'm struggling finding a really good Syndication Reader/Manager.

According to a recent check of my OPML file, I have over 400 feeds I track. I don't remotely read every single feed as soon as there is a new item posted, but I find aggregating all the information there makes it much easier than checking 800 pages every day. In some respect, it's bookmarks that tell me when a site has new info.

I've been using SharpReader for the longest time, which is tied to the .NET framework and while being mostly perfect, development on it has ceased, it hasn't changed in over a year and it tends to eat up CPU.

Things I liked about it:

• Updating: Despite having over 400 feeds to manage, it used multithreading to update all of the feeds in a matter of 1-5minutes. I tried using FeedReader earlier today and it took almost an hour to go through all the feeds.
• Timing: SharpReader let me update my feeds as recent as every 15min. I believe an "hour" is a set standard but a lot can happen in the world in that amount of time. I don't abuse it - and I actually do make use of the more frequent updates.
• The Little Things: Being able to do things like easily open threads in new windows, mass move, sort, copy and filtering threads.....searching all the aggregate news.....spotting similarities between feeds....were all very important. This is why I'm reluctant to move on to another reader

Another item that would be nice would be something that is a Web-based application with these features. I'd like to be able to access my news anywhere like my email, IM, del.icio.us links etc.

So.....what do other people use? Any advice for a power user?