If you haven't checked it out yet, you should really take a look at

http://feeds.scripting.com/rankings

Basically it's a site that allows you to upload your OPML file and share it with others. The link here shows the top 100 feeds people subscribe to. You can also go to each person and see their OPML list. You can also see who subscribes to your feed. Sadly, it seems that only 5 people subscribe to me, which is even less than my imagined 10 readers :)   (but then, Lutz Roeder's feed only has 3 subscriptions so what do I know)

Anyway, I just discovered some very cool feeds from there but I think it's still little known. So, what do you subscribe to? (BTW: you need to manually enable sharing your subscriptions so that you will be counted as a subscriber to someone else's feeds) 

(This is not aggregated on the main site so that I only bother the people who actually subscribe to my blog)