Here is the obligatory list of favorite links. 
<p>
Mathematics:
<ul>
<li><a href="http://www.geom.uiuc.edu/">Minnesota Geometry Center</a>
<li><a href="http://mathworld.wolfram.com/">Eric Weisstein's Treasure Trove </a>
<li><a href="http://planetmath.org">Planet Math</a>, the Best Math Site Ever.
<li><a href="http://www.cut-the-knot.org/content.shtml">Cut the Knot</a>, a fun collection of mathematical proofs, problems, and puzzles.
</ul>

Blogs:
<ul>
<li><A href="http://www.blogger.com">Blogger</A>
<li><A href="http://www.bloglines.com">Bloglines</A>
<li><A href="http://www.livejournal.com">Livejournal</A>
</ul>

Computers:
<ul>
<li><a href="http://www.slashdot.org">Slashdot</a>
<li><a href="http://www.wired.com">Wired</a>
<li><a href="http://www.ars-technica.com">Ars Technica</a>
<li><a href="http://www.tomshardware.com">Tom's Hardware</a>
</ul>

Net Comics:
<ul>
<li><a href="http://www.penny-arcade.com">Penny Arcade</a>
<li><a href="http://www.alessonislearned.com">A Lesson is Learned but the Damage is Irreversible</a>
</ul>

Online commerce:
<ul>
<li><a href="http://www.amazon.com">Amazon.com -- you know it owns j00.</a>
</ul>

Muds:
<ul>
<li><A href="http://www.andreasen.org/bartle/">The Bartle Tester</a>
</ul>

Science:

<ul>
<li><A href="http://science.slashdot.org">Science at Slashdot</a>
</ul>

Search:
<ul>
<li> <A href="http://www.google.com">Google</A>
<li> <A href="http://www.technorati.com">Technorati</a>
</ul>

General internet utilities:
<ul>
<li> <A href="http://www.mozilla.org/products/firefox/">Firefox: the best browser</A>
<li> <A href="http://www.gmail.com">Gmail: Cool webmail</A>
</ul>

Security:
<ul>
<li><a href="http://www.securityfocus.com">Security Focus</a>
</ul>

Fun Stuff:
<ul>
<li><a href="http://www.chick.com">Chick Tracts</a>
<li><a href="http://www.theonion.com">The Onion</a>
<li><a href="http://www.fark.com">Fark</a>
<li><a href="http://www.memepool.com">Memepool</a>
</ul>