when talking about rss readers, a few blogs that immediately comes to mind is zenhabits and problogger
lol they are nothing when compared to Engadget or Tech Crunch! Engadget - 1644K Tech Crunch - 990K Boing Boing - 436K Mashable - 138K 43Folders - 118K These are just few of the very big list of bloggers who have gained the big 'K' in their subscribers list. I would be coming up with a detailed list on my blog very soon.
yeah the number of subscribers engadget and techcrunch has is crazy. Gizmodo has quite a lot too. as does readwriteweb (95k)
Here's a list of Top 40 sites according to Feedburner. http://franticindustries.com/2007/03/24/top-40-sites-according-to-feedburner-stats/
Keep in mind those are extremely inflated due to Google Reader's feed bundles: http://mashable.com/2007/10/15/google-reader-stats-are-bullshit-with-proof/