First I will add a plug for https://www.bloglines.com/ â" RSS feeds where ever I can log in, via HTTPS. Great for those feeds I read whenever & everywhere; and for those I only check when waiting to board the airplane. In my bloglines collection I have around 400 feeds, which will grow after looking through these threads. :) Some selections that hopefully no one else has mentioned:

Amusement:
http://failblog.wordpress.com/feed/
All about the Fail

http://lolbots.com/?feed=rss2
Robots making the LOLz, though not updated often.

http://lolgeeks.com/?feed=rss2
Geeks making the LOLz, though not updated often.

The latest limerick database entries - http://peeron.com/tickers/limerickdb.xml

The Triumph of Bullshit - http://bullshit.tumblr.com/rss

Diesel Sweeties by R Stevens - http://www.dieselsweeties.com/ds-unifeed.xml

PHD Comics - http://www.phdcomics.com/gradfeed.php
Ever spent time in academia? You will relate to this web comic.

Unshelved - http://www.unshelved.com/rss.aspx
A web comic about a library. Ssssshhhuusshh!

Indexed - http://indexed.blogspot.com/atom.xml
Take two (or more) topics and compare them using graphs & charts â" full of insight & lolz.

Computerworld Shark Tank News - http://feeds.computerworld.com/Computerworld/Shark/Tank
Many stories, full of humor and face palm

Overheard in the Office - http://www.overheardintheoffice.com/atom.xml
Instead of what was overheard in New York, now worldwide and from your office.

Common geek topics (those blogs that seem to hit all the topics days or weeks before you see them on Slashdot):
Didnt You Hear... http://www.didntyouhear.com/feed/

The Daily WTF - http://thedailywtf.com/rss.aspx

Global Nerdy - http://globalnerdy.com/feed/

Shopping:
http://content.dealnews.com/dealnews/rss/todays-edition.xml
Many of those geek toys you need

Newegg.com daily deals: http://www.newegg.com/Product/ProductList.aspx?Submit=DailyDeals&nm_mc=OTC-RSS
Need I say more?

Slickdeals: http://www.slickdeals.net/rss.php
Need I say more?

Woot! http://www.woot.com/blog/rss.aspx

Dumb political stuff:
Homeland Stupidity: http://feeds.feedburner.com/HomelandStupidity
Government gaffes, bureaucratic blunders and incumbent incompetence

Groklaw: http://www.groklaw.net/backend/GrokLaw.rdf

Declan McCullagh's Politech http://www.politechbot.com/info/rss/politech.xml
Also not updated often, but on target when it is.

Cryptome: http://cryptome.org/cryptome.xml
You can get lost here for hours

Music:
House of Blues: http://hob.com/venues/clubvenues/lasvegas/
The RSS feed for the local House of Blues, which tends to have the newly added concerts days before you hear it from anywhere else.

Real Synthetic Audio: http://www.synthetic.org/rsa.html
EBM and Industrial net radio show podcast â" great stuff IMHO

Other podcasts:
Connexion Bizarre - http://www.connexionbizarre.net/rss.xml
Distorted Circuitry - http://razorgrrl.com/itunes_podcast/dc.xml
Cyberage Radio - http://www.cyberage.cx/cgi-bin/cybercast.cgi/index.xml

What else but the:
Defcon Forums - http://forum.defcon.org/external.php?type=rss2
The forum for those that attend, or want to attend DEFCON

WWdN: In Exile - http://www.wilwheaton.net/mt/index.xml
Yes, THAT Wil Wheaton.