You can use Google Reader to create a bookmark for your browser that knows what you want to read and whether or not you’ve read it. I’ve done this for the sites I read most often. I click one bookmark and it takes me to the new stuff on those sites. Not the feed items but the actual sites. Click it again and it takes me to the next new item on the next site and marks the item as read. There is something to be said for actually looking at the sites themselves and not in a feed reader.
Go to your Google Reader settings -> then goodies -> choose a tag that you’ve given to some of your feeds from the drop down menu -> drag it to your menubar -> click it. -> repeat